I just read over the part of the OP talking about GOMAD.
Just wanted to give a short version of my story in regards to that.
I don't really recommend going full GOMAD (maybe some extra milk to your diet everyday, but one gallon of milk, especially whole-fat, is downright dangerous).
I did 1 gallon of milk every day for about 5 weeks back in Summer 2011. I doubled my squatting weight and increased my weight on everything else. The strength I gained was startling. However, I put on about 33 lbs. of weight in that month, mostly water, and I had bloodtests done before the diet, after the diet, and 4 months after the diet. I was completely fine before the diet.
My blood results 5 weeks after starting the diet showed that my liver was in a lot of stress from all the milk. I was ordered by my doctor to cut out high fat foods, like whole milks, also tylenol or alcohol containing products, and any protein supplements, like pills or powders, until it was back to normal.
From what I understood, there are two major enzymes from the liver that signal liver stress/disease/damage, ALT (alanine aminotransferase) and AST (aspartate aminotransferase). Low levels of ALT are normally found in the blood. But when the liver is damaged or diseased, it releases ALT into the bloodstream, which makes ALT levels go up. Basically the same case for AST levels.
My ALT enzyme levels were 196 U/L when the normal range is 9-51 U/L.
My AST enzyme levels were 57 U/L when the normal range is 13-40 U/L.
A week and a half after my diet, after following her orders, they went down to 123 and 53 respectively, and then 4 months later, down to a normal 30 and 20.
I just can't recommend that anyone go on the GOMAD diet for longer than a couple of weeks at most, or at least to go full GOMAD. Maybe 1-3 extra glasses of milk a day, but NOT a whole gallon. Your liver is not designed to process all that junk every day and I wouldn't want to find out what would have happened if I had done it for as long as some people claim to do it. I had only planned to do it for about 5 or 6 weeks but I was shocked at how much it was stressing my body. It just wasn't worth it for me. I'd rather gain mass much more slowly if it means being healthy. Everybody's body is different, though, so this is just what happened to me.
But for me, in my experience, the best way to build overall strength are heavy squats, supremely heavy deadlifts, monster heavy bench, and weighted pull-ups.