With Millenicom you can use the service with no contract and if you buy a modem or mifi device you can restart the service very easily when you need it. If it works at the farmhouse then you can eliminate the DSL and use your cell phone for voice and the mifi for data. The slowest cable connection is going to be 10x as fast as mifi/EVDO.
We found that using a Cradlepoint 802.11n router with our USB modem installed we got much better signal strength as the modem was able to use the three antennas of the router instead of its tiny internal antenna. Last week I installed a marine antenna on the roof of our camper and its cable feeds down to a RF booster which runs off 12v. From there the antenna cable adapter connects the booster to the EVDO modem. I get overall about 4x the signal strength with this setup. I use the same equipment but with a house roof mounted antenna on a mast when at home. We cannot get cable or DSL or 4G, or cell phone service for that matter where we live which is 5 miles from the nearest town. We are stuck with whatever the local telco, AT&T decides to provide which at this point in time if plain old telephone over twisted pair wires circa 1960.