Your original idea should be more than adequate, but perhaps you should just look into using SSH of some form, as opposed to Apache (if you'll have a laptop or be accessing it from a trusted computer you can install things on).
If so, check this tutorial here:
http://howto.diveintomark.org/remote-mac/
Basically you just need some VNC clients. The video there is about Apple products, but the items linked to should apply well, and the dyndns service is definitely something you want to look into.