Are you asking whether you should buy the Hunter 340 now, snowbird on it for 5 years, then go cruising? Well, I'd say go for it... just get rid of the Mac 26x while you can get good money for it... after you sail on a real sailboat you won't want to go back to the water ballast, combo deal.
You have a lot to learn about sailing and sailboats..... do it on the Hunter, you'll know in a few years if it will do what you want it to... if not you'll have a couple more years to find another and get that one ready.