I come from a background of doing art/craft shows for over 20 years including 14 years full-time on the road, all of it was selling items that I had handcrafted. I didn't sell knit objects but I've been a knitter since I was 5...oh lord that's a long time ago...
Yes, there's a market at art/craft shows for hand knit objects. And yes, there's probably some shows around Boulder Co.
BUT, BIG BUT!!
It's not something I am going to recommend that you two look at however for the following reasons.
You're coming in from Thailand for 4 months of travelling. Importing enough stock to make it worthwhile that has been made ahead of time in Thailand is going to be fraught with import regulations, brokerage fees, possible import fees etc. etc. As well most of the better shows require that the crafter prove that what they make is made in the USA which you won't be able to do. The craft show business has been so fraught with imposters (claiming it's handmade in USA when it's not) that the good organizers now require copies of invoices for raw material.
To arrive empty handed and then start making enough stock to make it worthwhile to pay the booth fees, acquire booth equipment (tables/table covers/interact machine/display booth etc. etc) is going to be nigh unto impossible. Knitting is very labor intensive, there is no way your wife can have sufficient stock on hand in 4 months to do one show let alone multiple shows.
If you're only planning on doing a couple of shows when you're in Boulder it becomes even more economically unfeasible to do so and you would definitely have stock left over meaning that any small profit made from a show would all be tied up in inventory. No one does a show and sells everything in their booth.
The better shows are all juried. This means that the show organizers judge from photographs and sometimes in person, the work to determine if it belongs in a show. Even if you started right now, the deadline for the better shows for this summer is likely already past. I booked shows up to a year in advance although some had deadlines that were closer to show date like 4 and 5 months out. The not so good shows that don't jury have a preponderance of non hand crafted products made offshore and misrepresented as being handcrafted. They are more like a flea market than anything else. Despised by true handcrafters and populated by an attendance that is looking for a bargain and a day out, not high quality merchandise that is handmade.
Knitting itself is so very labor intensive that it is almost impossible to make even a dollar an hour of labor on it. While small items sell better, when you take into consideration the material cost and then add the time it takes to make an item times a decent labor rate the item has to be sold for more than what the general public is going to pay for it. To make any kind of money from a craft business, one has to find a product that is fast to make and can be sold for enough money to make it worthwhile.
You are planning on a whirlwind tour of multiple states. As a knitter, I can assure you that you cannot knit and sightsee at the same time. I can't even knit while a passenger in a moving car because of the motion of the vehicle.
Basically, IMO you can either be a tourist or in business, one or the other!