I would recommend rotating through a ruck, cals, stretching, and grass and guerrillas with stretching and foam rolling being the most important. I don't want you to get injured so just make sure you are really listening to your body.

Depends on what you like. I have worn those in uniform for a long time. Also, just remember most people have field boots and garrison boots. When you are in the field, you unblouse your boots.

Start at 35lbs and work up to 60 lbs.

You should be able to run 6 mi in 44:06 just wearing PT gear, ruck 6mi with ABUs a weapon helmet LBE and 55 lbs ruck at a 15 minutes a mile pace. For training I would run up to 10 mi at 8 minutes a mile pace at a minimum and for the ruck just keep it to the standard.

Alice frame with a XL pack.

I personally like the regular just because there are not a lot of times that you will really need the goretex in training. If your feet are getting wet in training, then your whole body is also wet because you are either getting spayed with a hose or going through a creek.

The ones I use are keens (super comfortable but not as durable as some) and Lowas which are more durable but more expensive. Another recommendations, Salomon’s they makes several boots that work well.