I'd pay somebody for a trailer. Don't foget, you need to flip it over. You also need to get into the cracks for the shackles, etc. It's easy to ignore them and paint over, but that's where the rust will breed. Also consider that there is absolutly no rust protection inside the tube. If the outside looks crusty, imagine what the inside looks like!
If you have more time than money, the little portable blasters will work. I think (guess) they will draw around 15-20 cfm. That's more than most home compressors are capable of sustaining. You'd be better off renting a very serious gas powered compressore and blaster. Even the smallest gas powered compressor will be putting out close to 1,000cfm. Now you can get the job done in a couple of hours instead of days.