If your tires are the original on a 2006 trailer, they should be replaced. Tires have a useful like that is either time or miles... you can see when you've worn the tread down with miles; it's not always apparent that an old tire is about to come apart. Trailer tires have a hard life - they don't last as long as the tires on your car or truck. They are often the "weakest link" in a trailering setup. They also have a different speed rating than auto/truck tires. So, how far you can tow? If all is good with the tires, hubs, and bearings, you can tow all day long, day after day. If smoke pours out of the bearings or your tire comes apart while going down the road... you've gone too far. Not trying to be a smart ass with that comment; just take your time when towing. Make sure the tires are at their max inflation. Stop frequently and check the bearings, either with your hand or an IR thermometer. You don't have to drive the speed limit... we are in west Texas currently, and the speed limit here is 80 mph. I rarely exceed 65 mph when towing, and am usually closer to 60 mph.
Plenty of us here have towed our boats coast to coast. Take your time, take care, and keep an eye on things.
Congrats on the new boat!