Is 50 dollars per motel, 50 dollars food stipend as well as 50 dollars spends per day adequate? Could it be finished upon less? (not together with automobile let charges) How most rounded off will automobile let be for 3months, as well as is it probable to dump the automobile in Phoenix afterwards collect up an additional in Dallas? Is 3 months ok for such the grand trip? Please advise

3 months is fine.
But your spending rates are way too low. Lets be reasonable.. we’re in 2010. Not 1974!
$50 on motel? What city are you at?
Car rental alone will be something like $40 a day including insurance. You cannot drive a canadian car to drop off in the USA. You can pick up a car in dallas and drop off where? Not in Canada you don’t.
Really, you’re looking at close to $2K alone in car rental charges.
Better if you just buy a car in Canada and then drive through the US and back to Canada with insurance. It’ll be cheaper than renting.