atbear, I am posting here assuming that you will be keeping the standard size tires. Based on what you said and reading between the lines if I am correct most of the time when you get in your truck you will be driving a virtually empty truck in the city but most months you probably actually put more miles on the truck at 75-80 mph on the interstate. Also, I went to the Boston Whaler site and they currently have 3 models that could be your 23' boat which you rarely tow and these boat, motor, and trailer weights fully loaded would come in at 5000 to probably up to 6800 pounds. Also knowing how flat your part of the world is I would in the 3.5 eco 2wd recommend the 3.15LS rear end unless you insest on racing from red light to red light. This would get you around town just fine and be perfect for your interstate driving and still comfortably for your seldom and flat boat towing trips that I doubt are even as far as 200 miles perform well for you. If you get the 3.5 eco 4x4 I would get the 3.31 open axle for all of the same reasons. In the eco wether you go 2wd or 4x4 I would NOT go higher than the 3.55 axle ratio. If you choose the 5.0L engine then I would not consider anything other than the3.55LS 2wd or the 3.55 4X4. No matter what truck you buy you need the trailer tow package NOT the max tow package. And also get the factory trailer brake controler. Also you will need to pick up the after market trailer tow mirrors that just slip on over the factory mirrors for your rare boat towing trips. I suspect that your boat though very light weight for a boat this size is 8 1/2 feet wide. Remember that this is my 2 cents worth based on the available info and my reading between the lines. By the way, all Boston Whalers are very nice boats, I wish I was close enough to go out on it with you. I usually make it up to the DelMarVa peninsula every 2 to 3 years to go salt water fishing with my cousin. Good luck to you.