I would cancel the plans and look for another place. You could also buy a small property that does have DSL and build a tower to beam to the house with microwave or directional wifi. Or see if you can rent space off an existing cell tower to do it. Probably expensive though.
When I was house hunting one of the main things I was looking for is making sure it was close enough to a central office or an AFC so I could get DSL. If not, at least cable. There was one house in the boonies I really wanted and it did actually have ADSL. Turned out to be too big of a fixerupper though and was kind of far from work. Where I am now I get decent service, even though I'm pretty far from the CO. There's a nearby CO but I'm actually connected to the main one, where interestingly, is where I work.
LTE is not really a viable option unless you are lucky enough that they have unlimited packages. Normally the caps on cell data are ridiculously low so it's not really usable as an every day Internet.