Mr Mix - I was looking at the possibility of remote access to stuff on my NAS but I can't get a static IP from my ISP. You dangle a carrot with 'other options', go on then. I'll bite.
Well, remote access to your NAS without DDNS or Static IP could be a little tricky.
However remote access to a machine on your LAN from which you can then connect to your NAS is certainly most feasible.
Go have a poke around with TeamViewer which is free for personal private use. You can connect remotely to computers without needing to open anything inbound and I'm pretty sure you can transfer files with it too.
To put it politely, unless you're planning to run a VPN to your DDNS, I'm not entirely sure I'd recommend putting a NAS or Computer "directly" on the internet by opening inbound ports ...
