I have a Verizon Mifi and added a Wilson Sleek to boost it's signal. Works great. And I think most will agree that Verizon has the best overall country-wide coverage.
As others have said, don't bother with CG Wifi.
I used to ride bikes. In hot and cold weather and also rain. Loved every minute. A bike was my only transportation for several years. I'm sure a bike WILL work for the most part for you. But I think a toad is a better solution for what you are considering. To me, getting groceries would be the biggest obstacle. I know you will do your major shopping before getting to the CG, but if you stay for a week or longer, then you might need a major grocery run before you intend to move to a new CG. Carrying groceries, including frozen, maybe also a 12 pack of beer, soda, water, etc. could be a real challenge. I'm not saying it can't be done, just that it might not be fun after the first time. And the farther you are away from a town, the less fun it will be.
Also consider that you may be many miles down a gravel road, especially if you like state and county parks, or just want to be off the beaten path a little. Gravel roads are absolutely no fun on bikes, although an Enduro style bike would work much better then a street bike.
I suspect you are going with the bike plan so I'll just suggest that you make sure that whichever RV you get has the capacity and ability to tow a small toad in case you change your mind at a later date. I've seen a few Smart Cars in my current CG so I'm thinking one of those could be a lightweight option.
Don't worry about backing up with a toad. Just don't do it ! Unhitch when you get inside the CG and park each one individually.
Tim