IMO, even a short collar will be a benefit. Go with either 2x4 or 2x6 for the structure and skin it with some nice hardwood. I went with 2x8 for the structure of mine when I put it together. I also don't have much for woodworking tools, or experience, but I got it done. I did get help putting the collar onto the freezer when it was time. Simply remove the hinges from the back of the freezer body and secure it to the collar. I also used some adhesive backed neoprene insulation (1-1/2" thick IIRC) between the lid and wood and the collar and the freezer body to make for a better fit.
Benefit of the collar is how it's easier to drill through for your gas lines. I have both a CO2 bottle (20#) and nitro mix bottle (60 cubic) sitting outside the keezer. Means more room for kegs and such. Plus easier to monitor the gas pressures and levels that way (don't need to open the keezer to check). I used bulkheads to bridge the inside and outside of the keezer, so that I can easily change the lines if I wish. Not to mention the passthrough holes are also smaller.