"how do bands find older audiences - "
unfortunately,unless you actually were successfull in your 20`s and doing a "comeback" and preferably have had at least one hit to fall back on,or you played in a band called Anvil,then you`re stuffed.
Read the gig guide in Classic Rock magazine-it`s the 80`s again and the punters who can afford the tickets are the cashed up baby boomers-the "older audiences" you speak of.
we are an original 3 piece in our mid to late fifties who do support gigs occasionally and have found the main thing going for us is we use the best equipment available to get the best sound possible and never play without a soundcheck-never.
as for our audience:most are muso`s ,easy to spot,huddled in their little groups checking out the gear and the chops and we play for them-if you can keep your peers interested you are doing your job-if we can get at least one person up dancing and the muso`s nodding then it`s a good gig.
Ageism is sad but you can always close your eyes at a gig and just listen-all the rest is just smoke and mirrors anyway.
i would come and listen to your band if you were a bit closer.
cheers