Just keep in mind that there is a trade off with the Model 3, and an "affordable" version (I assume you're referring to the SR+) only has a real-world range of about 180 miles on a full charge. So while you can reasonably keep your charging stops to 15 to 20 minutes, you'll only maybe be traveling 100 to 120 miles between stops. The bigger issue is if you are in an area that still has wider gaps between Superchargers. Then you're back to the ~180 miles between stops but about an hour's worth of charging. Essentially, I'd suggest reaching out to some Model 3 SR+ owners who have actually traveled with them and ask about their experiences.I'm fine with the range on the 2020 Bolt, more than enough for me, even when taking trips. The only problem I have is the DCFC charge rate. Capping out at 55kWh and only getting even that below 51% charge is just too slow when traveling. I'm fine stopping every 170 to 200 miles if I can charge up in 15 to 20 minutes.
I got the Bolt as a commuter car and it is working great for that. But I really have no interest in taking it on a trip that would be over roughly 200 miles one-way. I'm okay with charging at the destination where sitting may not bother me, but if I'm on a 500 mile road trip I don't want to have to stop every 170 miles and charge for an hour. I'd be perfectly fine stopping every 170 miles and charging for 15 minutes though.
Our ICE will be due for replacement in about three years. I'm hoping to have more options then to replace it with an EV that has a DCFC of 150kWh or better. Right now the only affordable choice available to us to get that is a Tesla M3.
At this point, there really isn't a sub $40,000 EV that meets your expectations for 170 to 200 mile legs with only 15 to 20 minute charging stops, and I don't know of any that are on the horizon. Even the standard range Mustang Mach-E looks like it's going to take 30 to 40 minute stops to do 200 mile legs, as does possibly the fastest traveling affordable EV, the Hyundai Kona Electric.