I've been limited to NA planes over the last 10 years or so. My own Beech (IO-520; 285hp), a friend's 172/180hp, and another friend's NA 310.
The Beech would do mountain trips, but I would only try to get up and out of the mountains in the morning. We had enough margin in cool air and reasonable winds, and it was a good enough plane for my loads back then (pre-kids) but we sold it and I'm not eager to get back into one at today's prices.
The 172/180 is actually a really good plane, but it's still a 172 and you still need to be cognizant of the limitation that a 172 has, especially when you're up high. You can have a surprisingly decent useful load on a light 172 with the 180hp upgrade and GWI. Still, not a good hot/high hauler. I'd take it to Durango (OOC) because the in/out is from/to the flatlands and you can land at Farmington if you're not happy with how the flight is going.
The 310 is good. But, as with most twins, when you load it up and fly in thin air, it won't fly well on one engine (T310s are different; I really like T310s). We did a trip to a ski resort in a long valley a couple summers ago. I landed at an airport at the bottom of the hill, rented a car, and drove the family up to the resort. Had we flown in, losing an engine would have required a forced landing in a high valley. Very limited escape routes and not a lot of room to return to the airport. At least going to the lower airport would have given me options to land on roads or farm fields.
Prior to 2013, all of my flying was in turbo'd twins (Cessna 300/400) and turboprops doing firefighting and UPS cargo. Both of those jobs were in the mountains. The fire was exclusively a summer thing and the fright was all year around.
So, maybe I just got spoiled with TSIO piston engines. Those anemic climb rates in NA singles are just less and less comfortable as I get older.