I am in the process of buying
a documented boat right now, and it is currently endorsed as recreational, but I am going to send in my "exchange" paper for "coastwise" endorsement so I can run some charters when I want. It's only an additional $29 for the endorsement. The USCG said they already have the original builders certificate on file which proves it was built in the U.S. (I got lucky!)
I went through the process of applying for a Jones Act Waiver on a previous boat...$500 non-refundable fee for an application to US congress, write up a short description of your intended operation and geography it will potentially cover. Then 2-3 months since they have to post your business idea in the federal registry and require a 60 day period for comments (for instance, if other operators in business/geography complain that you will injure their business). They did end up granting me the waiver.
Your real expense will be when you try to get insurance
that covers a charter
operation, and you will also need to get a certified rigger to provide an acceptable rigging survey
As others have said, call the USCG. That's what I did, and they recommended I go ahead and apply for the Coastwise...obviously, no problem still using the boat "recreational".