Just adding on (most of this has already been mentioned).
I did something similar to this. I was a contract instructor and used a 182RG to fly to week long classes around the country. I was based in the Chicago area at the time and my longest trip doing that was to Boston. Although most were around 600nm. I had a "provisional", refundable ticket that I just kept rolling over in the event of weather or mechanical problems (when you're teaching the class, you simply CAN'T no-show). Most of the classes were in major cities so direct flights on United of American were almost a sure thing.
One of my motivations for flying myself was that we couldn't book the flight home on Friday until 6pm because you really never knew when you were going to finish on Friday. But 99% of the time, we would be done around lunch. Flying commercial, that means going standby on Friday afternoon (good luck with that), or killing 4-6 hours until your flight home. Often, I wouldn't get home until 10pm or later. But when I flew myself, sometimes I would be home for dinner! So I get the time issue you're dealing with.
Having said all that, there's no way this is practical for a number of reasons.
You say it's miserable sitting in a middle seat between two big guys? Have you spent 5 non-stop hours in a SEP airplane? I've done 4.5 in the Cessna and I would not want to do that again. Even in my Velocity with the nicest, most comfortable seats (and expensive) seats I've ever sat in, five hours non-stop week after week would wear me down to the point that I wasn't looking forward to the flight (and when you get to that point, you shouldn't be flying anyway). Besides, I guess it's the vibration, but most people don't have the same bladder endurance in a piston airplane that they do in a car. So don't assume you'll be able to make that 5 hours non-stop. Yeah, you can do gatorade bottles. Been there, done that, not a fan.
Buying the airplane is only the start. Hangars in both locations, fuel and maintenance. Insurance on a high performance, retract for a low-time pilot is going to be eye watering. And 10 hours per week (assuming you flew every week) is going to put you in engine overhaul range in about 4 years. I haven't looked at overhaul prices for a TSIO550 but I bet it's impressive these days.
Weather is going to prevent a lot of flights (even with FIKI). And when it happens while you're away, then what? You get a ticket and fly home? Now someone has to make the 90 minute round trip drive to get you home. And the 90 minute drive to get you back to the airport so you can get back to work. Or you spend the weekend away from home? And then the weather messes up your flight home the following week and you get to deal with it all over again. I have spent many nights away from home waiting on weather when I would have been home in bed if I had flown the airlines... Then again, the reverse is true too (but not nearly as often).
My suggestion is to get a CFI, rent the closest plane to what you're thinking of and go up for five hours, non-stop. And be focusing on flying. No watching videos or reading books. Because when you're doing this for real, you'll be the PIC. Who knows, maybe you'll really like sitting there for five hours. Then you just have to make the money work and figure out the logistics of cancelled flights for weather or maintenance.
My suggestion is to spend that same money on upgrading your tickets to first class. But where's the fun in that?
