As the question text reads, I need to enable remote access on my RPi over the internet without using port forwarding. I have a custom OS and can not do a general update without overwriting some of the customization. I think that using weaved is great but it will not find the software using apt-get unless I do a general update first. I might be able to update a specific software if needed but not sure what those are.
I found that when using the apt-get update command does not actually update any software but instead the index of the repository so it is fine to use. Now given an updated repository I can get the software I need easily. This is as opposed to apt-get upgrade in which it will update (or "upgrade") the packages to the newest versions and thus ruining the customization of the system.