Hello ZeroFear 
I would agree with the suggestion that you visit for at least a few weeks (longer if you can) to see if it is truly what you want. Braga is a beautiful city, with many friendly people (natives and expats), but there are also questions to ask yourself.
What type of visa are you planning to apply for? You'll want to do some research to see what is most appropriate for you. I'm not sure if you are familiar with NHR (basically tax breaks/structures for new and some returning residents), but that has changed significantly over the last few years and is now geared toward professionals and specifically omits those with passive income (which would be the D7 visa). Will you be working? Does your profession fit into a category where the new NHR would be beneficial? If not, consider the tax implications of moving to Portugal for your particular situation.
Do you plan to drive/own a vehicle here? As Strontium points out, there is transportation to Braga from multiple places, but Braga doesn't have a metro system like Porto. I believe there are buses in the city (we live in a rural area about 30 minutes away), but make sure that they can get you where you need to go with a reasonable schedule. If not, you need to look at options. Will Uber or Bolt suffice for your needs, or will you need a vehicle? FYI, driving will probably be quite different from what you are accustomed to and parking is a blood sport over here. You will also need to convert your driver's license when it expires.
You also need to consider where you want to live-- downtown, a quieter neighborhood, or somewhere rural? Apartment or house? What do you need to have in walking distance? For us, we needed to have doctors and a hospital within a 20-30 minute drive, and grocery stores closer. What are your requirements for housing, and what are deal breakers?
Do you have pets? That is a process to get them over here (almost as involved as getting yourself here), and if you are renting, that could be a factor in where you are able to find housing. Are you bringing more possessions than you can put on the airplane (or boat) with you? How will you get them here if you are, and will you actually need them (your current cookie sheets will probably not fit in an oven here). Start thinning your possessions now, then do it again a few more times before you actually move. If you're like us, you'll still unpack a few boxes you probably have no use for here.
Have you thought about insurance? Most of us carry private medical insurance (WAY less expensive than the US, but still a consideration. The public health care is there, but the wait can be long and sometimes tricky to navigate from what I hear. We are still waiting to be assigned a doctor, and have been here for a year. Others have been waiting much longer.). Renter's and auto are less expensive in my experience, but still necessary. If you are going to travel outside of the country (especially back to the US), consider that in your expenses.
Also, you mention a disability. Not knowing what it is, I would consider any accommodations you have/may need and find out if they are available here. I'm not saying they aren't available, but things are much different here as far as that goes. Can you explain what you need in Portuguese if necessary? I mean no disrespect, but there are days when I have difficulty expressing what I need at the grocery store and have to rely on the patience of the Portuguese and sometimes strangers who speak both languages. Fortunately, people are very kind here.
Are you patient when dealing with bureaucracy? Plan on at least double the amount of snafus you are imagining right now.
I hope I haven't overwhelmed or discouraged you, but these are some of the things to consider when seriously contemplating a move here (or any other foreign country). Personally, the hassles have been well worth the privilege of living here, but others may have different opinions. Feel free to reach out if you have questions.