The federal home mortgage interest deduction is probably a much bigger impact on the available budget than the state's renter's credit. The renter's credit also dies out quickly
as income goes up -- for 2014, the threshold is $58,060 for a household (in 2010, the average Minnesota household had an income of $57,243). Meanwhile, the homestead tax credit only zeroes out once household income reaches $107,150, and that's still at the state level.
I'm not a huge fan of the idea of a mileage tax, mostly because it's been tied to a desire to put a GPS tracker on cars to deal with the problem of crossing state lines. We aren't New York, though, and the imbalance between in-state residents driving elsewhere and out-of-state residents driving in the state is small enough that it can probably be ignored. Odometers have been regulated for a long time, so we can probably trust most people to just read off the value once a year (or some other regular basis) in order to pay the mileage fee. Some sort of spot-checking/auditing would probably be enough.
Right now, I don't have enough knowledge to say whether the infrastructure dollars are being divided between the Twin Cities and the rest of the state fairly or not. I don't think we have a good definition of what is fair to begin with (or if we ever will), so that makes it pretty difficult to decide. Many measures are inherently skewed one way or another. As of now, the dollar amounts are split roughly 50/50 between the two, and that's not too far off from the population distribution. Things are inherently more spread out in rural areas, though it's also usually cheaper to build out there.
At the same time, I think small-town residents are just as in need of walkable business and residential neighborhoods as many city-dwellers. A single-family home on an acre-sized lot can be just as out of place in a small town as it is in the city, yet you could transplant an apartment building from the Stevens Square neighborhood of Minneapolis into a small town and no one would be the wiser.
Anyway, we're still spending too much on new
infrastructure in most of the state, while the balance should continue to shift towards maintenance and correcting safety issues. Meanwhile, more money should be put into public transportation within towns/cities and for intercity travel, and there should be better funding for walking/cycling infrastructure that actually allows people to get to and from real places rather than trails off in parkland.