Bruh, I'm not even in yet, and I've come to peace that a lot of my time spent will be what most people would call boring.
If you wanna fight, you sign as an 03xx. As you pointed out, it's peace time, so 03's are probably gonna do a lot policing for cigarettes, room inspections, etc. It's just the reality. Ain't no one needs killin right now.
In the next 4/5 years of your enlistment, someone may be deemed by the U.S. to be "need killed". Who knows... we've been at war for over a decade so everyone seems a little gun shy.
Now if someone DOES need a killin', and your an active duty 03, there's a good chance that you'll see combat. From accounts I've heard, units in hostile areas get contact a few times a week, for minutes at a time up to several hours. If shits hitting the fan four hours, you're probably not a happy camper though, I wouldn't know.
In between these possible encounters, you can probably expect to do further boring shit like cleaning your weapon, pting, more policing, watch, patrols with no action...
What I'm saying is, even if you get your wish and manage to get in the shit, ~90% of your time is gonna be spent doing nothing particularly exciting.
Bottom line is that if you wanna be a cowboy gangster 24/7, you better score high enough on your ASVAB, be a pt God who can run marathons and swim 500s in under 5 minutes, and be likable enough to be accepted by the teams of high speed guys in force recon/marsoc, seals, delta, or whatever.
So realistically I'd say:
-Be in great shape and mental discipline -do real goodly on dat dere ASVAB and have no physical defects, prior trouble with the law -enlist as an 03xx -breeze through boot and hope to volunteer as an 0321 (or fuck that, you're a badass... enlist as a 0321 for a guaranteed try-out) -stand out as a leader and hard worker in your unit -pray to Chesty for war -serve honorably for a few years and hope you get a shot at force recon or marsoc
That's about all I got for you. I'm a lowly, nasty pool boy so I could be completely off track with this. Any currently serving or veterans are more than welcome to correct me.