you can clip anything to anything. the guy I bought a bed from had an s10 clipped truck. I thought I had taken more pictures and maybe I have them on a work archive but this is the truck. It wasnt stellar work
the point is, you can install anything, and you can also install anything badly. a completely bolt in setup wont work very well if you dont have any mechanical discipline, which can go for both a bolt in MII setup and for the bolt on s10 frame swap (which I think is the $1500 setup mr48 is referring to).
Ask yourself what you want to do with this truck. If you are looking for a drop dead gorgeous hot rod at the end, a custom front suspension might be the way to go.
Purists and old timey hotrodders prefer the MII (or dakota) route because it can be very cleanly installed on the original frame. Thats nice, but even the least expensive kit bought in parts will be over 2k by the time you buy all the required parts like a steering rack and arms and tie rods and brakes. and then you still need to put it on. plan for replacement parts by asking what the rotors and pads are from, tie rods, control arm bushings, etc. MII and dakota use steering racks, so ask about that part too, so you know what to tell the guy at the part counter.
An S10 swap can be done cleanly and safely. Its not just the cool kids doing them either, skymangs thread in the sticky section shows how it can be done to give you a good solid driver truck. There will always be the old traditionalists caterwauling about the swap but here is the thing, if you arent planning a nut and bolt restoration and want a great way to go cruising and have fun, and upgrade to disc brakes and power steering, and find all your wear parts at any part counter anywhere, it makes a lot of sense. The frame is easily set up for a V8, and if you keep the rearend that is one less conversion that is needed because it already has an open driveline and highway gears. I recommend doing a ball joint and bushing refresh on whatever s10 donor you use, its inexpensive, under 400 dollars for every wear item and can be replaced in an afternoon. You can buy a running donor and offset the cost by selling body and drivetrain parts, or check with the local salvage, around here an entire s10 roller frame is $250-300 because there are just so many of them in salvage yards owing to the fleet acceptance of the truck. the entirety of my s10 swap on my 65 did not cost what even the crossmember setup from porterbuilt fabrications cost, which by the way is totally worth the price and is a work of art in its own right.
as far as clipping, the original rails can be kept, I dont have a how to for you but it can be done by any shop that will swap in a camaro or g body. if you are doing it yourself a lot can be learned here even if not directly applicable to an s10 clip, so look around.
for clipping or frame swapping, keep legality in mind. The rules for finding the VIN on trucks are pretty clear and were developed so that people with newer and more valuable trucks did not steal an undamaged truck and swap VINs with a totalled truck, using part or all of the donor and thereby laundering the stolen parts. Although these rules are not intended to keep a guy from combining old body parts with more modern frames, you WILL have to adhere to the rules. Here in Kansas it is very simple, keep a record of where the donor parts were purchased and any VINs from the parts, a title or bill of sale for a frame, and when the truck is done have that VIN assigned as part of your build. This will help when selling on, if you ever do. I have done this for my S10 swapped 1965 and it is easy. Lots of guys talk scary about title issues, but the rules are there to catch chop shops, not the hobbyist.
again, anything can be done poorly. there is a 56 ford with a MII around the corner from my house that is done so scarily that I asked the guy to call me whenever he is going out so I can stay home. There is an S10 swapped truck at a local dealer that is gorgeous and has been done cleanly and is worth the 29k they are asking for the truck. Think about what you want to do, go cruising? win shows? sell on? and that will set the plan for your upgrade. Read skymangs S10 swap thread in the stickys. Look in the project section for MII swaps.
edit: I guess technically my 65 is clipped since we backhalfed it. So I can speak from experience of both an s10 frame swap and a clip transition. Build things cleanly and strong and no one can knock your ride.
body mounts:
clip transition:

fish plates for strength:

cleaned up