Iif you want to do the most straightforward and simple job possible I'd get a Surly Singleator:
To provide chain tension, and a single speed cassette hub sprocket and converter:
Then you can leave the rest of the bike as is.
OR:
Flog the Trek complete, and get an OTP like a Fuji Track (or similar, I'm not up on what is current in that area of the market right now), in the long run this will be the cheaper and easier route to follow. Nothing wrong with a Langster, really, for example.
Iif you want to do the most straightforward and simple job possible I'd get a Surly Singleator:
To provide chain tension, and a single speed cassette hub sprocket and converter:
Then you can leave the rest of the bike as is.
OR:
Flog the Trek complete, and get an OTP like a Fuji Track (or similar, I'm not up on what is current in that area of the market right now), in the long run this will be the cheaper and easier route to follow. Nothing wrong with a Langster, really, for example.