Roody,
Has pretty well got it pegged. It will depend on what you need vs what's available, and no two towns/cities/metros are going to be the same. I know of a town of 10k in NC that is very doable by bike and has just about everything you could need...except access to any form of interstate/intrastate mass transit. It is 35 miles to the nearest bus station or train station and over an hour45 miles to the nearest commercial airport and 1.5 hours65 miles to the nearest international, even though it is on an Interstate and has 2 major US highways running through town.

Another town that I am fairly familiar with, has a population of 4,000 is in a very poor part of the country, is very livable, actually has a better selection of stores than the 10k town above, has 4 Amtrak trains a day and 2 Greyhounds, nearest airport is about 45 minutes40 miles, nearest large one just over an hour50 miles, it is on a major US highway and about an hour45 miles from the interstate.

FWIW in both towns the weather is mild enough you can ride year round with little problems. Another thing to consider is your employment, is it something that can be done anywhere? or is it regional or town size specific?

You will have to make your choices and decide what you need versus what is available.

Aaron