Turning onto 15 degree sideroad - Can it be done ?

Well it's been many decades since I had geometry, but IIRC, at a fifteen degree slope, your 10 foot rear overhang is going to be on the ground within about 5 feet of the rear wheels starting up the slope. The front won't make it either.

Of course, you could take the unit you are thinking of buying for a test drive and cautiously try and take it up your drive way. You'd want to have a representative load on board.