Hey Steve, I just wanted to add my 2 cents worth on this topic.

My wife and I have now completed several week long trip in the Pacific NW. We both paddle CLC Chesapeake 16's. I'm about 20lbs lighter than you are. We specifically picked these boats because they are full volume boats that are also very nice for day to day paddling. You wouldn't believe how much gear we pack in these things for our trips.

Specific to your question though, comfort is the single biggest factor. Most boats you are looking at are well designed and will be safe for the long haul. The real question is, can you sit in it for hours on end.

You noted the speed thing, so let me share this, an average of 3mph is realistic over distance. 5 is not. Brian Shultz is an incredibly experienced paddler, who tours in a boat designed by him, for him that is easily half the weight of the boats you are looking at. Please don't expect similar performance from yourself until you have done some longer trips and have a track record to support it.

I'm in great shape and can comfortably push a CLC 16, fully loaded (100lbs of gear) at a little over 3 in fair weather over distance. I can push it to 5 and have tracked myself at 7.5 for short distance. But for planning purposes I shoot for 3 or 3.5. Don't forget to subtract or add current.

Look for volume, length in the waterline (creates a good hull speed), some rocker (allows the amount of water being pushed to vary based on load), a high front deck for foot clearance and a comfortable seat. A beamy boat with high initial stability is more comfortable over distance as you spend less energy stabilizing.

Just my thoughts!