Research split database, 'how to split a MS database' or something similar. The way I read your post, some things you say are counter intuitive. You cannot put an Access form on a pc - only a database (which should be the front end only). Yes you can password protect the back end (be), but I'm not sure you know what the 'be' is. The most difficult part can be sharing across different LAN's (locations) but it's not clear if that applies here. When a novice says 'creating the tables is the easy part' I can't help but think 'you don't know what it is that you don't know'.
If you plan on sharing this across different geographical locations I'd say sure it is doable, but I can't help think that you will find yourself in over your head. I don't mean to be dismissive, but after many years of experience I think I have some idea of what you're up against. Last but not least, if the db will be used on a wide scale and must house attachments (documents or images) or security is of utmost importance, Access as the be is not even the right tool.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.