Yes, Bert, the Kwik Build/Fast Assembly kits can vary greatly. I had purchased a "Rat Patrol" Aurora model kit for it's sand dunes and palm trees and oasis for my Fort Sahara/Beau Geste FFL collection years ago. As far as a complete kit goes, I discovered the tanks/Jeeps, and men were terrible quality. After watching a few re-runs of the T.V. show on YouTube, I decided I wanted to complete the kit with various current upgraded Fast Assembly vehicles. Here is what I discovered.

I like to put actual complete Tank Personnel in my vehicles, so I needed tank turrets with hatches that can be open, and a turret that actually allows a standing commander to drop into it (no half figures). The S-Models are more highly detailed and do just this, a two-piece turret open top and bottom. But they can be finicky! If I didn't care about the turret details, I would go with either Armourfast or Italeri which have a simple peg to hold the turret on.

I wanted real easy and simple for Half Tracks and chose Armourfast for the German Half Tracks and Italeri for the American Half Tracks. Italeri has pictures on the box, and Armourfast has sprew pictures posted. Jeeps I needed the machine guns mounted so went with a regular kit, but I think S-Models now has this much easier than what I chose (durn!)

After watching several episodes of The Rat Patrol, I finally figured out the German Tanks are actually Converted U.S. M7 Priest/Kangaroo beasts with armour welded on to enclose the guns. The only true 1/72 I could find are Italeri Fast Assembly, but out of production and very rare. They are a great kit, comes with two, and well worth the money. I found a couple of kits on eBay from a guy in Hong Kong, and lucky you, he's got one or two now for sale there.

Orion has some great German Panzer Tank Personnel figures. Much better than the pictures.

OK, that's my story. All that said, it's likely to be another year or two before I actually assemble/convert any of my vehicle kits to make the complete "Rat Patrol" set. So in the mean-time, good luck and have fun.

Fast build etc seems madly contradictory when people quibble about a few extra minutes in assembly then spend 2 days painting on chips and scratches in the most minute detail on what is often an inaccurate model especially in the track running gear area. For those who want quick to build board markers then they should be robust and easy to put together. A Dragon Jeep has very fragile axles yet the Heller/Airfix one is tough and still looks good. I have a Dragon Jagdpnzr IV and the marvellous tracks have now gone brittle so what price durability and strength? Surely a model can be accurate and strong and not overly complicated to build. How many truck models have accurate undersides and suspensions that take ages to build only to be invisible to most people looking at them. A completely concealed engine is another curious one. Tanks with all turret hatches opening but the poor driver has to use the vision ports yet another anomaly.
Dan Taylor Modelworks do enhancement kits for the S models A13 which come to about £16 on top of the S model price and look anything but quick and similar for the Crusader. They do look a 1000 times better though.

David

Bottom line for me is, I'm getting old, I'm legally blind in one eye so I have no depth perception & my vision is slipping in the other! I just can't be bothered with so much fiddly nonsense that a real kit offers! I had tons of models I was going to build when I retired & sold them all to pick up the FA kits instead. But now, I keep running into these horrid kits! The GAZ was awful with way too many fiddly parts just for, as you say, an undercarriage 99% of people will never see, + 2 tires do not touch the ground! It's a horrible model! F this, my Russians will just have to use easy assemble Italeri jeeps!

I really don't care about how the tracks look on tanks! It was always the worst part of building a tank; putting on that stupid track, (that you had to sew together because melting tabs last about 2 seconds!) & pray you didn't snap off any bogy wheels! I still have nightmares about putting together the ONE Airfix Churchill tank I ever attempted! & forget those multi-part ESCI tracks! I think a reincarnation of the Marque De Sade came up with that nonsense! All I want is a tank, jeep, truck, whatever that I can put together quickly that looks decent! Beyond that I am OK!

On the + side, I finally have my Dingo for Col. J.O.E. Vandeleur for my Market Garden set so I am happy!

A very ambitious project Garrison & good luck with it! Somebody has already assembled jeeps with machine guns mounted. They look great, but need figures. I would never totally replicate Rat Patrol vehicles because as you say, they are not really German vehicles from the war. This is one of those rare times when I would have to insist on historical accuracy for German vehicles to go with the fantasy Rat Patrol! Were I to do it of course!