Hi,
I am a newbie when it comes to networking and router configurations.
I have a 750GL router and I would like to use it manly as a VPN server at home, to be able to VPN-into my home network from outside (both to get access to internal resources as well as routing my traffic securely when I am traveling and accessing from unsecured hotspots).

The setup I am having right now at home is
AIRPORT is giving out DHCP addresses for internal network in the range of 192.168.0.*

Ideally, I would like to put 750GL into the system and eliminate one of the switches at the same time: Which means, I do not want Mikrotik to do DHCP, NAT or introduce any other subnet or any other routing complexity into my home network, just act as a switch.
At the same, I do want it to have its own static IP on the network as well, and AIRPORT EXTREME will be configured to forward port 443 to this IP. Mikrotik will handle VPN
connections on this port and will get external clients into the internal network.

Am I asking for too much? Is it possible at all?
If not, what is the closest setup to what I am asking?
And how to do I do all that?

Thanks a lot!
Dmitry

This is doable but not over port 443. Depending on what VPN service you use (PPTP, L2TP, or OpenVPN) will determine the ports you'll need to forward.