Well, I can help a little with your techno issues, I think. I'm a self-employed real estate appraiser working out of my house for the past 17 years. My work involves inspecting homes and then ALOT of computer time writing reports and accessing the internet for data, MLS & email. I frequently work at the "Southern Command Center", my Catalina 36 and I am fully functional when working on the boat.
Internet - I use a cellular air card for my laptop which is fast enough for general web surfing, downloading and watching TV from network websites or Hulu without any lag. Most marinas still offer hardline phone lines, so you can also get DSL over the phone line. If you're lucky, your marina will have free WIFI, but don't count on it. You can also piggy-back off a dock neighbor's DSL with a wireless modem. Just make a deal & kick in some money so it's a win-win.
TV - Yes, dish TV works fine on a boat which is tied down, it doesn't move that much. Think about the distance to the satellite and you can see why. Many of my neighbors have a dish. Since I have a house, I use Slingbox to watch my home TV from the laptop, also without lag. Lately, the phone companies have come out with services like FIOS which gives you cable TV through your phone line, so that may be an option as well. I think they offer deals if you get the TV & DSL in a package. BTW, since the digital switch, I'm getting GREAT network reception form my rabbit ears.
FAX - You didn't mention it, but I love Efax. About $ 150/year and they turn your faxes into emails which you can retrieve from anywhere.
as an aside....
Location - Think warm, why kill yourself if you don't have to. A 27-30 ft boat gets awfully small when you are snowed in for weeks at a time. Why do that?
Boat Budget - Sounds low to me, even for a Catalina. Consider the total cost after all repairs & deferred maintenance are covered. If you can swing the payments, consider a later model/better condition boat. Catalinas hold their value well if well-maintained. Example: I paid $ 75,000 for my 1991 36 in 1999 and was recently offered $ 65,000. Not bad after 10 years. Just a thought, and the loan is deductible as a primary residence.
Working on the boat is completely doable....and FUN! Enjoy,