Thanks for the advice, I totally forgot about mines in favor of more weapons. I do not like USF tanks, which focus on mobility but can't really flank as well as infantry. Because they are really squishy and probably won't get any veterancy with my bad unit micro.
My use of tanks consist of attacking behind my infantry screen, but I always miss-micro and usually chase and get kited, then killed.
I've thought about the pack howitzer, and I'll be using it as a later strategy, manpower allowing.
Manpower bleed is a huge drain with my kind of playstyle, infantry. I plan on capturing little ground with 2 rifles/group and holding that with sandbags or pits with MGs. My idea is that I can win small battles and push on the enemy retreat.
1) Mines win games!
2) You can flank with tanks, especially on a map like Crossing. Just need to know what AT is where and to knowingly swept the area/routes you're using.
a) don't chase and get shit killed. no need to chase excessively. It's better to take ground and preserve your shit rather than risk your own stuff, potentially losing you the game.
3) Pack howitzer is good, but it won't stop a blob
4) With 4 rifles, that's a formidable amount of infantry, but by the time your fourth rifle came on the field, you had enough fuel for captain but only ~100 mp. Consider making a second RE right away or after the third riflemen squad.
a) With this build, you have a an extra 1.5-3.0 manpower income (because of the popcap difference between riflemen and RE). Additionally, this can allow you to backtech to LT (to get extra AI power missing from 3 rather than 4 rifles, but also, you get access to the .50 cal). Alternatively, you can go Lt - M20 - Captain - Stuart. This delays the stuart by 70 fuel (~3-5 minutes) but it's still viable. M20 can force your opponent to tech to T2 faster/build a raktenwerfer earlier, taking up some of their popcap/manpower but sacrificing their own anti infantry power in the early game.
Even with M1919s, you can still use your rifles aggressively, flanking, etc. I'm not watching past about ten minutes (I want to sleep), but in general I can say that, as USF, using your munitions is crucial. As others have said, use those munis! LMGs, mines (mines in doorways as well; maps like Arnhem, Kholodny, etc., put mines in front of important buildings' entrance(s). Also, smoke grenades are useful. LMG obers, falls, MG34s/42s, LMG grens on the field? smoke 'em. Any infantry that can close (LT, rifle w/ BARs, RE w/ BARs) will do great as well.
M20s are good because you can lay the M6 mine that disables vehicles and does high damage. Late game, building an M20 can be useful
just for those mines. Also, you can sub out the vehicle crew w/ an RE squad, grab an extra zook, then give yourself a nice helper for your captain.
In general, don't confine yourself to one build order. Give yourself options. Calliope commander and Pershing are also good in 1v1s (m1919, infantry mines, respectively)