Even if the RV park had 100GB service, bandwidth is going to be an issue if the park is full and with many uses bandwidth intensive applications like streaming.
You mentioned uploading. That is going to be your limiting factor in most cases because many high speed plans still have relatively low upload speeds altough that is changing. If you live at a fixed location, getting your own internet service is your best choice. Worse case, maybe the second line would have to come in to the RV park office but you put your own router there. Being nice to management always helps. The newest Apple Extreme has a directional feature that would help if you are close to the office. You could combine with a booster if necessary.