Shawnie, I think you will love Colmar, Strassbourg, and Luzern [Swiss spelling]. I agree with OP's that staying in Strassburg will offer more activities than Colmar, but do day trip to Colmar. It's such a lovely area.
Luzern offers so much, is beautiful, friendly, walkable, and safe. You can take the ferry boat to Mt. Rigi [one hour] and then the cogwheel train [30 minutes] to the summit. You can opt to take the gondola down, then hike thru pasture areas filled with the sounds of those wonderful cow bells.
There's also Mt. Pilatus, using the ferry boat, where you can also chose to take the cogwheel train up, and the gondolas back down. And the city has weekly produce markets, set around the lake, which are charming. The hotel rates include a mobility pass, which covers the local buses/trams.
Soon you be exploring which Swiss Travel Pass to buy, Half-price or Full price passes. [Full price covers the boat and cogwheel to Mt Rigi, but only half of Mt Pilatus, not sure why.] The full price passes are great, as you don't need to purchase tickets, nor validate, as you just hop on the boat, train that fits your schedule. [The scenic trains that you aren't taking are different.] You will discover how marvelous and efficient the Swiss Transportation system is, and how easy it is to visit surrounding Swiss cities, such as Bern and/or Basel, by train, [trains usually leave hourly.]
You are planning an incredible trip!