Move a PunBB install from local to remote hosting?

Hello all.

I've installed and setup PunBB 1.2.12 on my local machine to enable me to develop the forum whilst offline. I've made a number of adaptations to the code (tpl files, functions, etc?), mostly to suit my intended design, but also to enhance the general accessibility*.
(* I'd already started chipping away at 1.2.12 before I heard about the improvements intended for 1.3. I'll take a look, but I'm not sure I can face starting over again.)

I'd now like to move the forum over to my host space whilst I finish tweaking things.

How do I do this?
Would I upload and repeat the original 1.2.12 install process and then upload and overwrite original files with those that I've changed in my local install as well as upload any custom folders, docs and images?

(Presumably, I'll also need to customise some thing such as the MySQL login and pass.)

Also, what would be the best way to have the forum reside at the domain, but remain off-limits whilst I'm still tweaking?
I'd like to be able to use it at the domain root without too much fuss when the time comes to go live.
I currently have a holding page at the domain root and I'd rather keep that rather than have a htaccess password dialogue popup when users stumble on the site index.
Do I stash the install at a sub-directory (e.g. mydomain.com/forum) and use that as the base url whilst still testing?
Would I then simply move everything up one level (whilst maintaining the forum's directory structure) and change the base url to the domain root when I wish to go live?

What else would I need to consider when making the move?

Big tia for any tips and advice.