If you do buy a low combine Trailor and get a straight truck to pull it around.. If not just drive the sprayer... It sometimes isn't worth the investment for the travel.
Most sprayers will do 30mph and some will do more.
I did the hauling sprayer thing and it just doesn't work for custom work. If you could buy an apache or mechanical drive unit with speed. Save the 10 grand in outriggers.
When you can spray all day, and have large fields at 5-10 gallons of water, yout can get a lot of work done, where I am at it was a waste of time.
If you have to drive 40 miles to spray two fields that cover close to 600+ acres it will be great. If you have to drive 40 miles to do 120 acres in 6 fields your wasting your time.
Its an efficiency thing. Thus why I stated a straight truck... U then can unhook the Trailor and drive back for water.