As has been mentioned, adventurers (specifically hero adventurers) are great, good melee and ranged, and are available in taverns, either as adventurers or young nobles, etc. Also, they are available from the start, unlike knighthood orders. My smash, grab, and hold force consists of about 200 or so hero/ine adventurers. I sent Marius and 1,200+ of his buddies packing with minimal losses (and loads of prestige gain), I love defending castles that need a siege towers to attack, especially when just about every frickin' defender has a bow/crossbow and knows how to use it! After running out of bolts, I got bored and jumped down and sliced up their tower pushers!

And then their armies scatter away from you and you can hunt them all down at your leisure, well unless Livius Legatus brings a couple other buddies up to attack Sarleon in the meantime.
Keep them garrisoned at half cost till you need them, gallop to whatever fief is being sieged and play whack-a-mole with enemy armies. Which is important, because those guys aren't cheap. I find I can't really be at peace with too many factions at once, I need the loot from constant big battles! And besides, what's the point in playing if you don't like big battles?
Another strategy I have is to keep a bunch of high-end recruitable prisoners on hand, and then recruit them by the dozen just before you're going to have some serious battles so the morale hit is a non-issue. That's especially useful for defensive troops, I once recruited about 50 Ravenstern rangers that way, whacked them into Arvendor which I'd just taken, took out my field army, shredded a few armies, presto-changeo morale is 99 again and Arvendor has a solid backbone of defenders. Did a similar thing with Marleons and Sarleon men-at-arms later on.
And don't forget, once you can garrison, take a small mobile force to go rescue recruiting by freeing captives, especially in Jatu and Noldor lands, where I've seen groups of a dozen or half a dozen Noldor or Jatu with several dozen prisoners waiting to be rescued, not all huscarls, but a good way to get a mix of mid-range or better units in a hurry. Mystmountains are good too, when they have Jatu prisoners that can be recruited, you're as happy to have them on your side as you hate having to go up against them. And when they level up to Jatu warlords, well,

. Because loot is related to party strength (i.e. you get less if your party is stronger), this is also a good way to make money. I've gotten more valuable loot by defeating a smallish (20-30) coven of heretics with just my companions than I have from wiping out a 900+ 3 seers army with my hero/ines.