How much would it cost to refurbish the interior of a car and will it be easy?

My uncle and I are trying to refurbish some 50's Ford pick up truck that he got from his father and it's honestly a wreck. The engine has a hard time starting and when we do get it we have to wait for it to heat up, the radio doesn't work, the lock on the passenger side has to be unlocked from the inside, and the interior is just messed up. It's all ripped and stained. Anyways we know how to fix the engine and a the technical stuff but we have no clue as to how we're going to redo the interior. So I have a few questions:

How much is going to cost?

Can we the two of us just do it or are we going to have to take it to a shop?

I live in the UK, and there are PLENTY of "Wrecks to Riches" type shows on tv here. I'm amazed that so often this sort of question gets asked - the USA is the world-centre of back-yard engineering, why do you have to ASK if you can do this? IF you haven't done it before, then you need to learn how. You will have to strip many of the parts off the truck, clean and re-paint them, and re-fit them. That's All that a restoration is, essentially. Some will be no good, and you will need to hunt a replacement or use something that will do the job OK. How much is it going to cost? You haven't even shown us a photo!
ALL your work will be in vain if you don't strip it completely, take the body and cab off the frame, cut out All the rust and any twists in the frame, paint and protect it from rust, do the same with the body and then re-unite them. HAVE you got a large garage, about 25ft by 25ft square? Have you got a lot of time? Can you weld? Can you paint a car? Are you williing to buy all you need to do this? Are you willing to learn how to do it? Any restoration job will run you probably $20,000+ from a shop, and will still take them a LONG time as there's a lot of work involved. This is the sort of thing that you do BECAUSE YOU WANT TO, and if it takes you and Uncle a couple of years or even more, then it's the JOURNEY as much as the destination that matters.
The result will depend on what you want the truck to be. Input = output, in terms of effort and ca$h.

First things first. Buy the shop manual for the car. Or, at least the consumer how to book from Chilton or Haynes. They give how to repair problems like door locks, engine, etc… Also how to trouble shoot specifics. As far as interior? On modern used cars you can easily look up models of same body used by maker for different brands, Then go to a salvage yard and buy an entire interior. IE: You can use Buick seats for an Oldsmobile, Or Pontiac or Chevy. Widens available car search and increases chance of getting the right colors. Each seat should cost $25 to $50. Full carpets can be ordered from JC Whitney for an average $125 to $250. Same with seat covers and such.

Hi anything is possible however a good sewing machine such as one used by an industrial company might be the best investment. The leatherette can be purchased from some material supplies. The carpet can be from any carpet warehouse off cuts and parts are your department you reckon.

Cost depends mostly on how authentic you want the results: you can probably make it "acceptable" for under a thousand bucks.

Authentic interior materials/parts/supplies are readily available: I just Googled "supplies - 1950s Ford trucks - interiors" and got 3,800,000 hits… Looks like any of the first 100 can fix you up