Vintage Peugeot conversion help and tips please

Q - I know the frame isn't exactly top quality steel. Are any of the other bits worth much?

Q - Could I simply take off one of the chain rings from the front when converting or do i need a whole new crankset?

Q - I've not tried yet but do you think 700c wheels would fit on this bike?

Q - Any advice on what is a good reasonably priced flip flop hub (fg/ss) that will last?

Q - Any other advice or things i should think about before i start?

The saddle is worth a wee bit. The rest, not so much.

Possibly, yes. Depends on how the rings are mounted.

Probably.

Not from me, I'm afraid. Classifieds here are often a good deal though.

Keep it within a sensible budget, though you can upgrade parts later (ie. the frame, etc). Borrow tools where possible, unless they are ones you plan to use regularly.