Funny I'm familar had both those sleds. 6'6" bud had SS 670 the old doo F was great for the big man in the day but F has enormous ski lift when you push it but plenty of power. The 2000 Ski-Doo Grand Touring is either CK3 or S I had the 98 Ski-Doo Grand Touring 583 S & was a great sled for the day & 98 F3 700 CK3 which was good motor but hard rider. With CK3 & F you will be delighted with any rider forward upgrade sled. Not so much in WI mostly smooth trails but those sleds would be a load in WI Twistys & wear you down quick. CK3 & F in UP would be torture when it gets ruff so understand why 150 miles is a big day for you. Time to upgrade to rider forward & you will be in the 250 mile club.
I'm 6'7" and 300lbs and that's why I had moved to the 2-up . Playing with limiting straps always helped ski lift on power. The 2000 I had was a ZX chassis.
670 SS was by far my favorite motor, that thing sounded sweet and just pulled like crazy. Dad had the F3 600 and you're right about not being a good trail machine.
I was looking for a 95-96 Mach 1 or Z with the exteneded track just recently. I might change my mind after renting these MXZs. Not sure on the leg room with these rider forward machines though.
With just two of us going this year I think we can break 300 miles in one day...We are starting at midnight with a 8 hour drive from IL and then hopping on the sleds at 0900 to ride all day!!?? Might just keep our sled gear on in the car