TA fans, look here

I've seen you play PA, clopse. You wouldn't be sacrificing much

Every game that has a LAN mode can be played via the internet, asuming you either deal with relaying packages aimed at the server through router (not that easy) or set up a VPN (comparatively easy).

All programms like GameRanger do is dealing with setting up a VPN for you. Usually using a central server and the good old TCP-Hole punching technique (a classic of peer to peer communciation).

Or you could just port forward?

It is that setting up your own VPN?

Yes, you can port foward. That is what I meant with "deal with relaying the packages aimed at the server through the router". And of course you have to deal with finding out your public IP adress and other minor stuff too.
If you go to these lenghts you might just want to make a VPN instead. Same secondary work, applies to every LAN operation bidirectionally (instead of needing one forward per server per side).

Nope, port forawrding and VPN are not related. A VPN connects two local networks as if they were the same local network, tunneling the data through a thrid (insecure) network like the internet.

Ah, we'll isn't using a VPN slower? I've used hamachi in the past and I remember some slowdown from it, also it limits you.

I never really figured out port forwarding for TA, I remember last time I joined a game where someone port forwarded I actually had to port forward too, just to join.

Yes compared to Port Forward there is some slowdown. Especially if you use encryption. The usual overhead of VPN.
On the plus side once you have set it up, it just works. For every game with LAN mode without any extra configuration, wheter it was made 1995 or 2014. For every function of windows, including file and printer sharing. For all intents and purposes two networks that are conncted via a VPN are one big network. For your computer reaching a computer the one on the other side of the VPN is as hard/easy as reaching a computer on the internet or one conncted to the same router.

Ehh I prefer playing VS AI, but TA's AI is kinda underwhelming.

Mods really help it, TA: Zero especially, but then you gotta use their units too.

Have you tried custom AIs? (warning, 90's site design)

Can I install more then one AI at a time?

You can't have more than one active at a time, but you can use TA Mutation to easily switch between them.