The mill has a sliding table that is controlled by turning knobs. Lutach, do you think the mill I linked to is up to the task of milling CF?

Yes, those knobs actually lock to avoid it from sliding and messing up your job (The ones I've seen does that lol). The thing with CF is that the machines that CNCs it are very high RPM and the bits themselfs are somewhat expensive. This is information from some of my clients.

Could you recommend a good bit for starters to make a chassis?

I don't know what kind of bits Harborfreight has, but check with them first. After that just buy some scrap CF and test on them before using the good stuff.

just make sure the bit is carbide and you should be good