Transfer of Ownership for a Vacant Lot

[James Lim]

I am trying to acquire a vacant lot here in Florida that has fallen back in taxes, it seems that the owners have not paid taxes in 3-4 years, and this year a larger penalty was assessed for letting the lot go overgrown.  The tax certificate for the first 3-4 years has been purchased by an investor, and after talking to the county it seems like this year it will likely be possessed and put to auction.

I've managed to reach the owner through snail mail, who is an elderly couple who called me back and left a VM basically sounding like they don't want anything to do with the lot.  However, I missed that initial call and since then have not been able to reach them again.  So they live quite bit of distance from me, so if I was to show up in person to meet with them and see if I could have them transfer ownership of the lot to me, how would I need to do this?

Do I need a lawyer or notary, or is there any specific documentation I would need them to sign?  (They no longer live in the county that the lot is in).  The lot is in Florida and I just want to get all my ducks in a row so I can get all this done in one trip if possible.  

Also as a side question... is it possible to have a local lawyer have them sign paperwork and have it assigned to me?  A nominal amount of money might change hands to the current owners of the lot, but there might not be any either as their VM sounded like they just wanted to get rid of it.

Thanks for everyone's input!