Road Trip to Utah and Colorado from San Diego

Hello and welcome to RTA !

As you look around the forums you will soon see that we don't do 'best' or 'must see' as there are many great options and people's interests vary. You haven't told us anything of yours. Utah and Colorado both offer among the largest number of 'main attractions' anywhere, including many spectacular National parks including, Zion, Bryce canyon, Capitol Reef, Arches, Canyonlands, Mesa Verde, Black canyon, Rocky mountain and no shortage of scenic routes. What I would suggest you do is to open a good map and see what appeals, do a little research of your own and then when you have a few dots on the map, come back and we can help you put it together to fit your time frame. I would be looking at a loop that incorporates at least some of the parks and if you visit 4 or more, buy an annual pass for $80 as it will save you money.

You also need it to fit your travel style, the pace you want to travel at, some people like to keep moving and see a little bit of a lot of places while others would rather spend quality time at fewer places.

Enjoy the planning !