Back to broken bolts.
Worst case scenario is that one or more bolts have sheared off in the stub end (ie assembly that goes through your wheel and held by that big castellated nut). If thats the case (and its common), there are couple of ways to deal with them:
Try turning whats left of bolt ends with the end of a screwdriver (friction alone may give you enough to turn them and unscrew them). If they won't budge whatever you do, the only other option is undo castellated nut, knock stub end back through and get them out on a bench. Getting the stub back through again can be challenging....
I have to say I've done that job more times than I can count (on mine and others campers). I run with good quality bolts and I make damned sure they're tight. Its not a hard job but its just a filthy job and I highly advise you have a box of rubber gloves from the off. Then theres the annoyance of getting an earfull full of grease and/or joint swivelling and falling apart.
Keep the swear box handy.
Oh and there are a few alternatives to some of the items on your 'to do' list that won't cost the earth. When you've got a young family you have to cut your cloth. I'm a single working Dad so I know all the shortcuts.