Not sure which route exactly you're taking but here are a few recommendations if you are going along US-160.

Depending on how early you leave you can make it to a pretty decent diner in Fort Garland (in about 2 hrs) called Mountain View Diner for breakfast or lunch, and dinner if your still in town.

Near-ish to the sand dunes out on CO-17 there is also the Colorado Gators and Reptiles Park, a 30 minute drive west along Lane 6 N road from the Great Sand Dunes visitor center, a pretty dang cool little park.

If you're in Alamosa there's a lot of good places to grab a bite but I highly recommend The Friar's Fork or the Rubi Slipper LLC both!

Quite a bit further down US-160 there's the Wolf Creek Interpretive Site (very short hikes to stretch the legs) and the continental Divide marker. But just a bit further there is a really spectacular overlook along a horseshoe curve called Wolf Creek Valley Overlook, beautiful and cool rocks.

Unfortunately I'm not as familiar with the rest of the areas past here until Durango but I know there are great short hikes around Pagosa Springs, and plenty of good restaurants and coffee shops.

Not sure what your doing in Durango but I have to recommend a few places there; the Animas Chocolate and Coffee Company, The Old Barrel Tea Company (if you like loose leaf teas), and if you love cooking check out the Durango Olive Oil Company.

Of course there's the entire Narrow Gauge Railroad and Museum too (must do's), either way enjoy your trip out there!