Some great thoughts re: where to look. I recently met the woman at Atholton Elementary School who works with pre-school students, most of whom have learning disabilities, and she LOVES her job and school for whatever that is worth.

College park is going to have some heavy traffic. Use google maps on a computer and set the "arrive by" time to get a fairly accurate estimate. Know some days will go up, so a 25-45 minute estimated commute in that direction can hit extra traffic and be 1 hour. If you can depart after 9am it will drastically reduce driving time. Earlier departures don't help as much, but if you can avoid rush hour it will help.

There are a ton of camps and programs offered by Columbia Association and Howard County. There is also the opportunity to take classes at the community college - both for credit and for fun.

Library system is well funded and I think phenomenal. The East and Main branch are modern and rather nice. We don't have those soaring classical libraries (Columbia was built in the 70s) but it's also not the dumpy brick building smelling like mildew either.

400-500k is a tough budget. You're solidly in the range for town houses in some of the smaller older developments (the new ones are insanely priced). Houses up now start in the 500s and go up. However, if you're stretching your budget, remember your income taxes are probably going to be higher than Colorado, and a lot of the houses incur an additional fee for being assessed Columbia Association - a few grand a year, set based on your house's value. This does not include a CA membership, which is annoying that's an additional fee if you want to use the pools and gyms. I don't mind paying it since it goes towards maintaining about 95 miles of bike trails, a ton of tot lots and playgrounds, and a bunch of tennis courts.

Tips for the area are tough. I spent three years renting in Ellicott City before buying in Columbia - and we still spent a solid year house hunting. Sorry - it's going to be overwhelming... but your price point and commute sort of limits what's available - so just keep watching for newly available places.