True. Though even the natives here get a little short of breath when climbing stairs.

Just remember to drink LOTS of water. Really. I mean like 2-3 gallons per day.

The altitude really shouldn't bother you until you get above 10k. Since you'll be riding motorcycles, you probably wont spend too much time above 10k so you should be alright. If you notice yourself getting a little dizzy, pull over immediately and sit down somewhere safe til it goes away.

 

I can't speak for much of your ride south and east of Colorado (though I would spend one night in Taos, NM...just for fun and eat at Michael's). But....I'd really suggest you avoid I-25 through Denver (something I avoid at all costs). Consider taking Hwy 24 from Colorado Springs west to Hartsel - north to Fairplay - north to Breckenridge - northeast over Loveland Pass and down I-70 to Berthoud Pass - north to Winter Park - north to Granby - north to Walden - north to Saratoga, Wyoming and pick up I-80 there. Much nicer ride for your return...may add a little more time but you'd enjoy it a lot better.

 

The stretch of FL Panhandle east of Pensacola, all the way to Port St. Joe or so, is beautiful. Lots of cool shops and restaurants through the Route 30A area between Destin and Panama City Beach. East of Panama City is some pretty country too. Would make for a perfect turn-around point in your trip, depending on how far east you want to make it.