That's not ideal but I suppose it would work. I was hoping for some commandline parameters or some such so it can run without a window or in the tray. It's gonna be at high risk of getting closed if it has to run in a Window all the time. Oh, and I hope there's a way to mute the audio...
Right now they don't have a server client, there was on on the forums, but it was buggy and caused Goblin Armies constantly (I know because I tried it). They are working on making a server client, but for now you must just use the normal client. You won't have to worry about sound, as when you run a server it just shows the people playing on it and it doesn't actually enter the game. So if you are to host on your main comp, oyu actually need to open 2 Terraria's.
The game use to crash a bit before the most recent patch, but when 1.02v came out, since then my HTPC has been running it without being minimized for I think 5 days now with no issues. I just have Windows Midea Center running over the top and Terraria running behind it.
As far as port changing, I'm not sure, doubt it's possible now, but like I said they are working on a server client. The creators just made a post a few days ago on their forums about what they are working on, PvP content, other dimensions, Server Client are just a few of the things.
Also if you haven't hosted yet, I'm pretty sure you need Hamachi to host the way it sits. So anyone else thats wants to play with you will also need it. Here's a screenshot showing remote connection to the HTPC with it running the media server.