How can I work on new theme / not messing up current theme?
 

I've agree to remake a friend's blog and since I use this Atahualpa awesome-est-theme-ever for all my other personal blogs I'm going to use it for his. But I need to leave his current theme untouched until it's ready. How can I do this? I can't figure out how to preview a theme without having first having selected it for the blog and it's going to take quite a bit of time and previewing, if my experience using the themes on my other sites is any indicator. There's got to be a way, right? Something I just don't know about yet? Would appreciate any advice.

Best,
PJ

There is a plugin I have used called Theme Test Drive which lets you work on one theme while showing another. HOWEVER if you make changes to the sidebars for instance it may mess up the layout of the current site. The safest way to do this is set up a dev site, design away and then integrate it into the live site when you are ready.

I would suggest making a copy of his site as a sub domain and doing the work there. Once you have it set you could export the atahualpa settings and import them in the live site

Thanks you guys! So that leaves one big question:

Once I finish the design in a separate setup, how do I 'move the settings' from the new one to the old one? Is it a single file somewhere, a whole folder, or...?

PJ

You would have to install Atahualpa on the old site but don't activate
Export the Atahualpa settings from the dev site
Copy any images from the dev site to the atahualpa folder on the old site
Activate Atahualpa and import the settings.

This is a pretty simplistic list of instructions but it is something like a manual upgrade to Atahualpa as described in the updating forum.

Just be sure to have backups and of course if anything doesn't work quite right you can always switch back to the current theme.