But if you knew then what you know now and ony had $2k in your hand to start over... what direction would you go and what specifically would you buy first?
If t'were me, I'd begin w/ .22s. K22, Colt Woodsman or Diamondback, M1922-M2 or Winchester 52. Shoot a lot, or shoot a little; clean, fondle and admire, good for young or old, cheap to feed, fun.
Since you've got shotguns covered, I'd make sure to have a good hunting rifle around as well. Win 70 pre 64 or their Sears and Roebuck Ted Williams equivalent in .30-06 or .270.
Pick an interest to direct your collection, i.e., mil-surps, cowboy, civil war, hunting, colts, winchesters, mausers, EBRs, long-guns, handguns, LEO guns, etc.
Maybe collect something they aren't making anymore that wears a name brand, like Colt DA wheelguns? Or prelock N-frames? Or Lugers?
Here's some free unsolicited advice about collecting... keep it sparse but full of quality. (weed out and discard crap from the getgo) Learn and know how to work on (assemble/disassemble at least) each piece in your collection. Know the history and value. Find a kid or three and pass that knowledge and love on during your collecting years.