I don't think anyone could really say whether you moving back "home" would be a good or bad idea without knowing a few more details. You're pushing 40. You left home at 30. You weren't young when you left and you haven't gotten any younger since. You say that your hometown is "dying", yet "up and coming." That's completely impossible. Either it's one or the other. A dying person isn't making good progress. "Up and coming" means "making progress; will likely be better in the future." So your entire outlook of what it would mean to try and build a life there if you were to return makes no sense. Either it's getting worse (meaning that it wouldn't be a good place to live now, and will probably be worse in the future), or it's improving (meaning that it might not be a great place to live now, but might be better on down the line.)
What are the downsides and negative aspects to this place? Is the job market terrible? Is it a crime-ridden place? Has it seen a lot of hard times - businesses closing, people moving away, etc.? If that's the case, then it obviously wouldn't be a good place to live. It wouldn't be a good place to make a fresh start, and anybody who's currently living there is likely not very happy and not doing very well. If one or more of those things are true, then you ought to pick another place to resettle. Familiarity is't everything, and if you're looking to change your life, it's an overrated concept anyway.
You didn't mention anything about what you plan to do after getting resettled, or getting settled into a new place. What line of work are you in? What's the extent of your education? Those are factors that will determine what kind of jobs you'll be qualified to do and what opportunities will be available to you in different places. Without knowing anything about your experience or education, nobody can say for certain that the job opportunities in one place might be better than those in another.
You want to meet somebody. That's your top priority. Well, if that's number one, then you ought to look at the best places to live for singles. Where can you find the highest concentrations of single people your age? Then, compare that list with a list of cities and towns where the standard of living, cost of living, housing market and job market are in your favour.
Chances are that you left home for a reason. Making the decision to move 2,000 miles across the USA must have been prompted by something. Did you leave for a reason or did you leave because you were just looking for a change? Did you set off because you were heading toward something you thought was better, or were you just leaving because you were sick of the place? It sounds as though you haven't had a great deal of success in the past decade and in your mind, home is familiar, so it might make you feel all warm and cozy inside to go back there because the familiar is less threatening than the unknown.
There are so many different factors that go in to the decision of where we choose to live and work and center our lives. Without knowing anything about you other than the fact that you're single and looking to mingle, how could anybody recommend one town or city over the next one?