It is straightforward to set this up on a 'basic' router, in principle. You need to be able to set up port forwarding on it. You also need to either have a fixed IP from your provider, or have an alternative method of finding your dynamic IP on the outside network, such as using the DynDNS service.
Opening up any network to the outside world brings more risks than not opening it: but then if we were all that risk obsessed we wouldn't even connect our PC to the web at all. Obviously your file is only as safe as the security of your username and password. You can add other security limitations, such as restricting the IP addresses that are allowed to access it.
The wifi part may cause a problem of performance, depending on how fast, secure and reliable the connection is.
Regarding the port forwarding, is there a set port for filemaker that it uses?
Also, regarding wifi, this was my implementation plan, as we roam all around our facility. Any specific issues reported / known with wifi use?
Yes - port forward to 5008.
Do you mean the server, or the clients, roam around the facility? I wouldn't recommend that you have the server connected to the network by wifi.
Thanks for the port info.
I mean the clients roam, not the server. The server computer (not using fm server) will / can be hardwired to the network.
Remember that if a wandering client drops the connection it will not reconnect when you re-establish network connection.