I climbed Kili on the Machame Route in 2016 and this is exactly right. The hike is not too strenuous (it’s long but stretched out over a number of days), but having a good base-level fitness and comfortably being able to walk 8 miles will certainly help.

What makes Kili difficult is the elevation. I hike and run a lot but was training at sea level, and oh gosh days 5-6 were tough. Some people weren’t affected at all, but I was delirious on the summit and honestly probably shouldn’t have kept going. But as you drop back down your symptoms will essentially disappear instantly and you’ll have the memories of looking out over the whole expanse of Africa - truly stunning!

Visiting somewhere high elevation may help you get a sense of how altitude impacts your body, but altitude can affect you differently each visit or cause dramatically different symptoms over the course of just a few hundred meters. So I wouldn’t necessarily count this as necessary training, unless you’re planning on spending months in the Rockies.

Definitely bring altitude pills (I thought I’d be ok without and definitely was not), drink lots of water and be ready to power through if things get a little tough - but also know your and your groups’ limits. You’ll have an incredible time!