Yes, it can be done online. The property owner (blue book owner) needs to register with the online services and register you as the property manager and Yiu can register yourself every time you come back home after each trip outside your province and abroad.
You can get a one-year spouse visa at the Thai Embassy in the US with a multi-entry permit. You can apply every year for a new one in your country of (prime) residency. Once you decide to stay longer and oftener in Thailand, you apply for an 'Extention' of the visa you got in the US. Very simple, and very straightforward.
be over 50, put 800,000 THB aside for a visa deposit and plan for around 1,000,000 THB (or less) annual cash/pension/dividends/retirement payments to live a good and easy life. Many live on 500,000 and are living a happy life in Thailand. The most relevant question you need to answer first is: Where do you plan to live, settle down in Thailand. Like every other country. The costs of living in Phuket are very different to Chiang Mai or Baan Isaan (somewhere in the middle of nowhere). Same food, same m² house, same drinks, very different Lifestyle.
There are ways to extend the 'temporary import permit' with LTA. However, most decide to pay the fine of maximal ?.000 THB at exit. I know of a Swiss who drive his Gold Wing into Thailand before COVID and stored it at a friend's place, only to drive it out (to Malaysia) in October 2023. He paid the maximum fine of ?,000 THB and was over the border in 30 minutes. Not that I recommend it to do it that way, but that is what many are doing. I'm really not sure how much the maximum fine is but I remember 1,000THB per month up to maximum 5,000 THB.