Remote Management, Access, etc

I don't really have a specific outcome that I'm looking for here, but I would like to know where to start. First, I am trying to figure out the best way (software, OS X built-in, configurations, etc.) to remotely access a iMac at home from my Macbook. I have never done any remote management before, so I don't know too much about where to start. I've briefly looked into the system preferences options (file sharing, remote login, remote management, etc) and have played with each a little. First, what is the difference between remote login and remote management?

I want to be able to control my Mac at with as much administrative capabilities as I can. Should I use a VPN? I've looked into this the most because I want to have access outside of my home network. Is Apple Remote Desktop the software that I should be looking at?

One issue is that the operating system at home is Snow Leopard, and I am using Lion on my Macbook. What will this affect? I will eventually upgrade the other OS, but it would be better if I can set it up as it is.

If the VPN is the way to go, will I need to go into my home router settings and change all of the port forwarding configurations, or is there some software that will take care of that? I think I saw a program called Slink in the app store that claims it will cover the port forwarding configurations. I've heard that there are some security issues as well; how should I go about taking care of those?

Also, is it possible to have read/write access to an external hard drive connected to the home computer, with and/or without all the remote management set-up? It's not a server or NAS drive, just a regular mac-formatted drive.

Sorry for huge question dump, I'm just having a hard time finding these solutions in one place. Any help for any of these issues would be great. Thanks

To access a computer behind a firewall such as a home router you need firewall forwarding rules or software that performs reverse connections like LogMeIn or TeamViewer.

When you forward ports through your router you are now only protected by the security of your of username and password. This is usually a security concern as most folks either don't have a password or it is weak and also never changes. Also when ports are forwarded they can be detected by port scans on your public IP. When ports like 22, 80, 443, 5900 etc are detected they hacker assume the services behind those ports are listening and attempts brute force password hacking, hence the importance for strong passwords.

Remote Login is for console access only. It turns on the remote ability to access SSH or secure shell. Basically the terminal. Any system access at this level is considered a security risk as severe damage can occur. Forwarding port 22 is required for remote access using this method.

Remote Management can either be ARD access (Apple Remote Desktop) which requires two open ports of your choice, the defaults being 5900 and 3283. Screen sharing and reporting are two big features of this as well as an ARD console to manage several Macs in one application $80 on the App Store.
If you choose to configure Screen Sharing and not use the ARD program to access the macs then Remote Management will also allow the built in (SL and Lion) screen sharing or VNC access to the Mac still requiring port 5900 to be forwarded through the firewall.

You will need a firewall that supports VPN connections or the Lion Server application to have VPN capabilities from outside your network. In other words, a VPN server for establishing the incoming connections. VPNs extend the LAN or private network, but if file access is what you are looking for then be prepared for a slow experience.

All three mentioned will give you some sort of access to the shared drive attached to the iMac. You may find some suggestions unusable to you in their nature. Most would suggest establishing a VPN first to run either ARD or VNC over this way there is two factor authentication and VPN security for communication (though the built in OS X VPN is not the most secure).

LogMeIn free and TeamViewer are two options for reverse connections to the iMac from beyond the LAN. LogMeIn having more tools but TeamViewer being easier to use IMHO. These require no changes to your firewall.

Have a look at this thread http://www.mac-forums.com/forums/switcher-hangout/274026-accessing-my-mac-ipad2.html

The question related to ipad - mac connectivity but many of the solutions suggested support mac to mac connections too.

I think you should demo copies of Share Tool.

It's sorta like VPN, in that it establishes a sort of secure tunnel from your remote Mac to your shared Mac over SSH. All traffic is encrypted, and you can use either a password or a key to gain access. It can automatically configure your network in most cases, and you don't need a static IP.

Once running, Share Tool will have all your bonjour services show on the remote Mac: file sharing, iTunes, iPhoto, your printers, etc etc. just as if you were on your local network. It also includes a way to do secure browsing. You can also connect to other drives if you allow them to be shared via file sharing in Sys Prefs.

If you're handy with a Mac, you can configure things yourself to use SSH to do much of this, but it's not trivial, as you've probably noticed. The Share Tool thing just makes it all easier. Ditto with LogMeIn and the other services, although I haven't used those.

Remote "management" AFAIK is just the designation for Apple's Remote Desktop.