How far up and down the St Johns river can you travel on the houseboats??

You can go as far North as Jacksonville.

We rented years ago and was told we could go North as far as lake George and South as far as Lake Monroe. This is more than enough area to explore.

Not sure of the miles,,, but you can travel north about 6 hours to Silver Glen Spring,,, South to Blue Spings, less than 3 hrs,,,

I went all over I think you csn go as far as you like