I think the biggest thing I'm going to keep from American football rules (which becomes a big thing near the try line) is the removal of a "maul-in-goal" in 1885. Teams would effectively hold up players from touching the ball down for minutes at a time (because they didn't have a "use it" rule and I guess players didn't/couldn't pass the ball back in a maul), and so the Americans decided to make it so that a ball that crossed the plane rewarded a try.

New alternate American football rules! It's going to eventually take on the name of "Quarters Football" (or just football here in the Americas, but that's another story for when I get to it), but here's what I'm thinking of the development path of the sport.

I am eliminating the scrum entirely but maintaining a contestable breakdown. I have no research to back this up, but I feel as though Americans would approve of the violence but not the strategic or scientific nature of the game. Instead, knock-ons will be resolved in two ways. The first is an immediate turnover if the opposing team recovers the ball, something that already happens in rugby. The second will be a knock-on penalty, which occurs if the team who knocks it on maintains possession or the ball travels forward such a distance that it would be unhelpful to the opposing team to recover and set to phases.

In a spirit of compromise, the teams fielded will be shrunk from 15 to 12 (Walter Camp wanted 11). Shoutout Canadian football! This leaves 6 forwards and 6 backs (original rugby competitions from the 1870's featured 9 forwards and 6 backs, sometimes even a 10/5 split), and with scrums out of the equation, forward mass and the amount of people you can use to bowl over your opponent is no longer as important.

As previously mentioned, scrummages were uncontested beginning in 1877, radically changing the game and directly led to the down and distance rule. Instead of an uncontested scrum, I propose that they changed the rules of the breakdown to limit everyone kicking for the ball at the bottom of a pile.

Breakdown Formalization
1. A phase is declared over, and a breakdown is formed, when a player is tackled and brought to ground while in possession of the ball, and at least one player from each team is in contact over the ball with their feet on the ground.
2. Each team is allowed a maximum of two players over the ball during the duration of the breakdown. If a player from either side is legally pushed off the breakdown, they nor any other team member can re-join the breakdown. 

The rest plays out sort of like a modern ruck, where the opposing team can reach forward while remaining on their feet and attempt to steal the ball from the attacking team, while the attacking team will have to kick the ball out of the back of the breakdown (similar to how a scrum works). This allows for teams to contest every possession. However, it also allows for offloads (a player goes to ground and pops the ball in the air to a teammate, who can continue running with it) to keep a phase intact, which will come into play here with this next set of rules.

Field Quarters, Points, and Phase and Distance
When the player count shrunk from 15 to 12, teams kept 8 forwards and four backs, without seeing the opportunity for space and focusing more on the contestable breakdown. This created an issue of 1 back/2 forward pods, where a back would run with the ball and forwards would alternate taking command of the breakdown. Safety touchdowns remained an issue, so the American/Canadian governing body (more collaboration of the rules and international games between border schools) came up with three solutions to this new version of the block game:

Points system
- Safeties: 1
- Touchdowns: 2
-  Kick for goal/drop kick: 4
These points would be modified over time to be a 1/7/3 split, with a rouge added as an extra 1-point opportunity and penalty goals being considered 3 points.

Field Quarters and Phase and Distance
- The field was broken up into four uneven quarters (25/30/30/25), and teams had 6 phases to advance into the next quarter of the field (or the goal line if inside the opponent's 25), or else the ball would be turned over and the opposition would have a chance at a penalty goal or kick to touch. Phase counts would only reset if a team entered into the next field quarter or if they had received penalty advantage. This would drastically modify the way the game was played, shifting the game towards offloads, wider spacing and heavier reliance on offensive kicking to move the ball forward.

Kick For Goal Area
The next issue in the sport was that kicking far outweighed try scoring inside the opponent 25. Teams were unable to generate positive phases when the field became more compact, and many teams instead opted for simple drop kicks or waited for a penalty option that gave them a chance for penalty kicks at goal. With the pitch now reduced to 60 yards in width, teams were given the outermost 15 yards on each side of the 25 to kick for goal at any point (including conversions after tries) to increase try scoring. This was eventually moved back to the 40-yard line as kickers got better.

The field changes to 100 yards with 10-yard goal areas, kicks could be recovered in the goal area.
- The rules still hadn't helped teams score tries, as more possessions were now turnovers deep into team's own territory. While strategies would eventually allow for better redzone play design, rule makers were more concerned with the ability to recover kicks beyond the touch-in-goal line.
- This happens for a similar reason as in our timeline, but instead of the forward pass being the impetus for such a rule change, it's because teams want to recover kicks in their own goal area to generate more scoring opportunities. Before this, any kick that entered into the touch-in-goal area was considered dead. To incentivize more risky attempts, any kick that travelled beyond the goal area in full (without touching the ground) would be given a single point. This is the rouge.

Another rule that might need some explaining is what happens when a ball is kicked to touch or if a player goes into touch during a phase. Because there is no scrum and lineouts weren't invented until after the point of divergence, the attack would start in the outermost 15 yards of the pitch's width, parallel to where the ball was kicked across the touchline. The defense was allowed to start no closer than five yards (later ten yards) away from the spot of touch and could not pass the scrimmage line until the next phase.

Here's a graphic of the field dimensions. The lighter green is the exclusion zone for kicking to goal in the modern game at the academy/college and professional level. You also can't kick from beyond the goal line, but that should go without saying.

https://archive.org/details/football00camp

Love when a sport’s early strategy books are posted on internet archive and I can look at play diagrams and stuff and not have to worry about if I want to spend $100 to do that.