Small CC engines need rebuilt sooner than large touring bike engines. A 600CC motor can easily go 50K miles. But after that it's who knows when it blows.
The 4 cyclinder inline fours race bikes can have a less of a life if rev the **** out of them. I've had a few. My 600's could get 30-60 mpg depending on how it was riden. At 30mpg, I'm sure you have an idea.
Some of your big BMW R series or GS 1100 can over 100K without a rebuild. For that many miles, I'd look for a touring type bike.
I ride a Triumph Tiger 955i. It get's 45mpg. If you wanted you could change the gear and get 55 no problem. These are fantastic machines that can run well over 50K with little maintenance. For the distance you're riding, better get something that easy on you. The 600 rice rockets suck after 75miles.
Why not have a windshield, heated grips, top bag, saddle bag, GPS and nice soft seat?
Honestly, sport bikes are not comfprtable for long rides...I regeared...raised the handlebars a bit...added a Givi windscreen that was taller...and totally marsee baggged the bike. It was useful...more than stock...but day to day commutes would have been a real pain in the a s s...literally. Test ride, Test ride and the Test ride...even bikes you don't think you would like. Get a feel for the seating position...handlebar ergonomics...weight on your wrists...ect. You will come to the same conclusion. Weather protection...Comfort for extended miles...Tank size...and...usable secure storage space will be the deciding factors.
Definitely looked for some great used deals...someone who thought they wanted a bike but then changed thier minds. You can find some great deals out there!
2006 Jeep Liberty CRD...Founder of L.O.S.T.
OME 2.25" Lift w/ Toyo Open Country HTs 235/75/16s
ASFIR Alum Eng/Tranny/Transfercase/Fuel Skids
2002 Air Box Mod...Air Tabs (5) on Roof...(3)each behind rear windows
Partial Grill Block with Custom Air Scoop and 3" Open Catback Exhaust
Lambretta UNO150cc 4 Stroke Scooter