I think you are setting up yourself for failure. 4GB of RAM for a monolithic PDMLink server will not cut it even for 1 CAD user. I can’t even run PDMLink OTB just for my own development/testing. The fundamentals of PDMLink’s architecture must be understood before you attempt to implement it, unless you have a lot of time on your hands
If you had an experienced PDMLink admin (Business & Server) who understood your simple requirements--and a cooperative IT environment--it could be done in 2 weeks. If you are going in uninformed you have a high risk of failure.
You will get your feet wet and learn something as you stand it up. By all means if you are up for the challenge give it a shot. I’ve enjoyed learning the system. Sounds like you have the right attitude.
OTB memory allocation is not sufficient. The java VMs used by the method servers and Tomcat will “crash” if you try to do much without tuning them. If they don’t actually crash you’ll have excessive garbage collection.
You can try NetIdeas for a hosted PDMLink/ProjectLink solution.
To add to the previous installationresponses...you can certainly install PDMLink OOTB, but as mentioned, it will not be particularly functional nor tuned for your environment. Your hardware is also woefully inadequate, particularly for a monolithic deployment (including appropriately licensed Oracle or MS SQL server). You might learn something, but you may also end up not knowing what you don't know if you don't have some experienced guidance along the way.