SeaSalt, welcome to sailnet.
I'm retired Navy.
USN programs change all the time, the only way to get all the facts is to get them from a recruiter - and even then get them in writing, then check 'em by looking them up on the internet. Not saying recruiters lie, I'm saying even they get it wrong.
As to whether you can save money over 4-6 years to buy a boat - even when you name a brand and size - the answer is it depends. If you select a rate (job) the is mostly sea deployed you can save most of your paycheck, but that's not much at first. How much you can save depends on how well you resist the temptations dangled in front of young sailors in foreign ports
As to unemployment - keep in mind that ALL unemployment benefits are given based on the assumption you are actively looking for a job - and have terms that are not that long.
The other benefits for veterans are extremely dependent on your service, other than those that are wounded most vets with only one term get nothing.