Your question is a bit open - offshore fishing is very different of the coast of Southern FL than it is in New England if you are running to the Canyons. So I think a little more detail will provide you with better feedback. However, assuming you are comfortable running 35 miles off shore in your 260 then fishing is no different than running. I think your most important question is safety equipment. For me the obvious items are a must at those distances: Ditch bags, back up radios, EPIRBS, Radar, etc. in addition to typical fishing gear.
You might post this on a site like The Hull Truth to get safety and running feedback from outside the Formula family where there is some dedicated fisherman.