There are three of us regulars here on this forum who admit to 78--so welcome to the septuagenarian hikers club!

Lightweight is important at our ages; at least I just can't carry the weights I staggered under through the Washington Cascades back in the 1980's. Besides, one of the mottoes of this site is "Backpacking light is more fun!"

Do keep in touch with your doctor, especially when going to higher altitudes. You probably should allow more acclimatization time than the younger folks allow (although they are just as apt to need it as you are).

The home page of this site has lots of good info, especially the articles and gear lists listed in the left hand column.

Here's a link to Topshot's excellent article. Good for all beginners, not just Scouts.

Another good article on going light, from "PMags" of Colorado.

Mark Verber's enclyclopedic website is an awesome source of info on outdoor gear. It has budget gear info, too, at the end of each gear type section.