Your plan is a good one, Victor! We have moved around a lot over the years for work and we are planning a big move from Tennessee to Maine for retirement. This time WE get to pick the place. We thought about all the things we would need (affordable housing, good health care, etc) , things we would want (good knitting or craft shops, theater to attend, good library, etc) and, of course - people to know. It is always hard to try to fit in and it takes YEARS to make friends - especially since we don't have the children to run interference. It was hard to settle in here but the internet finally made a difference. Anyway, we took our fact-finding trip last October.
First, we stayed in a Bed & Breakfast since it is easier to talk to people there. The owners of this one were new to the city too so were eager to help. I belong to a spinning/weaving/knitting online website called Ravelry. Various groups post discussions so I did a search, before we left, for what was in Maine. A few groups in Portland popped up and I posted a note that I was coming to visit - with the thought of moving there. Several gals reached out and were happy to share information. One gal even invited us to her house then she & her husband took us to lunch and toured us around the city. Another couple, my Brother-in-law knew, also took us to lunch and toured us around. We had a ball!!
We also had a list of addresses to drive by. One was a Medically oriented gym - no prescription required. They had changed their name and we couldn't find it so I called them. We were invited in for a tour and were so impressed! They were so friendly and the place was amazing! Also - since my husband has Parkinsons, we were interested in the neurology support as well as any other support. Someone suggested calling the Maine Hospital Help line. I did, and they gave me several names to contact. I called one guy who said he wasn't involved any more, and was about to move to Connecticut to be near his children, BUT, he spoke to me at length then even called me back twice with more information!
Another thing we did - I had donated some money to a Kickstarter business start-up in Kittery, Maine. I donated enough to garner a tour of a Sake' Brewery. We made an appointment ahead of time and drove down one morning for our tour. Again, had a ball. It was super interesting and we sat and talked for over an hour. The owner was great! He also drew us a map and recommended several good restaurants for the trip back to Portland.
So, now we already know people!! You must have some hobbies or sports or health needs that you will be looking for in Colorado. Make a list. Do some research on line. Take the addresses and go visit. We stopped in the Scarborough Library - they always have community announcements - and asked about senior programs. One gal was very candid and told us if we were looking for state funded assistance, we wouldn't find it here. The area isn't wealthy enough to have a Senior Center. I wasn't actually looking for that but was hoping there were some groups that might take trips or attend concerts. She said the library hosts some things like that so - there are things too do everywhere.
After our lunch and tour, the knitting gal had her group coming to her house. As they filtered in we were introduced and several of them had the same Realtor to recommend. Since she was so enthusiastically recommended, we called her and met up the last day of our trip. She was fantastic - listened to what we wanted and pointed out a couple of neighborhoods we might like. We drove around after and thought - gee, we could really live here! I am so over the suburbs thing and are looking for a place where we don't HAVE to get in the car to go anywhere. Want to be close enough to the city to do things downtown but my husband doesn't think he would be able to navigate narrow streets & traffic so well - so we don't necessarily want to live right downtown. (they still have some cobbled streets in Portland too) This makes it easier to look at real estate on line as we have targeted several areas.
We are planning another trip up next spring - perhaps to do some house hunting. I would certainly recommend you make an extended trip and give it a serious look around. I have seen people post, on other forums, that they had vacationed there once and liked it, packed up and moved, only to find it wasn't like that all year round or it was very politically different! We have lived in Connecticut and Rhode Island so we have an idea of what to expect from New England. Its too hot down south and too crowded in between. Good luck and let us know where you land!!