The smartest addition to my toon was a wheel. I mounted a 12 inch pneumatic wheel and tire on the frame just behind the seat of my toon. You use the foot rests as wheelbarrow handles and just wheel the darn thing fully loaded with all the stuff you need to have with you. It makes moving the toon from the truck to the water mondo easy. The whole assembly cost me only $11.00 for the wheel tire combo at princess auto. Some free scrap metal I found for a strut, and $4.50 for an 8" stainless steel bolt I used for an axel. Total cost was less than $20.00. Time spent about a 1/2 hour. The fat pneumatic tire makes getting thru the sand and mud really easy.
You can buy a store bought wheel rig for about $50-$75 online.
I have bad knees and don't walk really well. With this arrangement I can easily get the whole rig into and out of the lake in jig time with minimum effort. I have even moved it easily with a large RV battery and a electric motor attached.
For a rod holder I use a Downeaster rod holder that clamps right onto the frame of the toon, just in front of the Oar lock.