Discussion really starts with budget.
Met a guy this summer biking across the US on a Surly LHT. With his gear, and without water, the bike weighed in at 95 pounds. Incredible.
He was over 60 years young, doing 100 mile days through the mountains of southern Utah.
On a budget? The vintage mtbs are a nice option. I picked up two 1980s Diamond Backs, both had braze ons for front racks. MTB parts and consumables are plentiful.