OK so for the old rope in gunnel trick.
First you glue and nail your oak gunnel onto the boat. This may require that you steam bend it, clamp it to the boat let it sit for three or four days to dry out enough for the epoxy to be happy, then you nail it onto the boat from the inside with bronze ring nails making sure that you avoid the center line of where you are going to put the rope.
Next you buy a 3/4" half round bit for your router, which has an edge guide. . . . next you think about it . . . next you think about it . . . next you think about it. . . . . .
The reason that you think about it is if you screw up this cut I don't know how you will repair it. It will probably involve some wood cut carefully and plugged into place. Me I thought about it for about two weeks. Then I got up (no serious drinking the night before) had a cup of coffee and when everything was calm I got the router out and made the cut. First I made some test cuts on samples wood to make sure that I had the right setting on the depth and the edge guide. I started the cut and did it all in like two passes.
Next you sand and coat the boat with two or three coats of epoxy and four or five coats of varnish. Then you take the rope, some 3M-5200 (tan color) and bronze ring nails and nail and glue the rope into the slot. You should be able to more or less bury the heads of the nails inside the rope by selecting which of the three strands that you nail through and using a drift pin punch nailing in between the other two strands.
Here is a photo of the end of the cut showing the rope installed and the cut in the gunnel.
Here is a photo showing going around the corner of the transom.
I recently completed a build for much the same reasons you mention. I wanted a general utility skiff to use in our creek. Shallow draft, load carrying ability, high stability and economical to run. I opted to build a version of the Old Wharf Dory Companies "Lumber Yard Skiff".
The boat is straight forward plywood construction. I modified the plans to clean her up a bit. This boat can be built rather inexpensively... I didn't go that route, but it is entirely possible. We've had her in the water now for three months or so and I am pleased so far.
try lady bug boats. I built a 22'er last summer his plans are a little rough , i made some changes in material and frames and finished her up a little defferently than he does . the plans were $75. but you grt dimensions for a 14,18, and 22 footer.