First off, you're DEFINITELY not too old. I ski pretty regularly with two different 70-year-olds who make it up (and down) the hill just fine. As a matter of fact, their many years of backcountry skiing are partly responsible for the fact that they can still hike up a few thousand vertical feet with a ski-loaded pack. The cool thing about late-spring skiing is that you can usually just pick a snowfield and then walk up as far (and as slowly) as you feel like before turning around and skiing back down.
As to packs, you'll see about an even distribution between people who carry their boots in their pack versus those who carry them outside the pack (either locked into the bindings or tied onto the outside of the pack). Personally, I prefer the boots inside, but that really limits your choices in packs and usually means a bigger pack than you would normally need for mid-winter day trips.
I have a newer Osprey Switch 26, which is a great pack for regular winter day trips, but my boots DON'T fit inside it
, so I use my old Vortex 2200 when I go on trips where I'll be hiking in something besides ski boots. That, by the way, means almost all of my summer and early fall skiing.
I agree about not needing a wide ski for summer skiing. Usually, you're after the lightest combo you can get, so you really don't need a big ski for the conditions you'll typically find. Practically anything will work. Short is good, light is good, wide won't hurt anything but isn't necessary.
I'm going to be skiing in Alaska for a day in the Aleutian Range next week, and I'm taking the shortest, lightest pair of skis I could scrounge together (some 163cm Black Diamond Havocs with Fritschi Freerides). Ski "performance" really isn't a consideration when you're summer skiing.
You honestly could put together a *summer* ski setup for not much money. Any short-for-you mid-fat ski from ebay will do. (I think the Rossi BanditXX/B2 is a great choice for this kind of skiing because it's light and versatile). Here's a new pair: http://cgi.ebay.com/07-Rossignol-Bandit-B2-All-Mountain-Freeride-Skis-166cm_W0QQitemZ370075207142QQcmdZViewItem?hash=ite m370075207142&_trkparms=72%3A1073%7C39%3A1%7C66%3A 2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&time out=1218564750292
Better yet, I just remembered that a friend gave me two pairs of Volkl something-or-others to sell at our ski club swap this fall. I think one of the pairs might be perfect for you. I'll check the model and length later today and post them. The skis would be CHEEP but have no bindings. You can always find a pair of bindings cheap, or you could buy my pair of barely-used Naxo Nx21's for $175. You could just pick up the skis and the bindings when you come here to Jackson for the Gathering this winter.
Anyway, summer skiing is fun. It's pretty cheap to get into, it's very healthy exercise, and you really don't need to worry much about avalanches if you wait until the snow is fully consolidated in the spring and you stay off (and out from under) steep slopes that are heating up in the sun.