Upgrading from Glassfish 2.1.1 to Glassfish 4.1

Question

Can someone please enlighten me. I'm trying to upgrade my Glassfish 2.1.1 to Glassfish 4.1. I've decided to do a side by side install as indicated here: https://docs.oracle.com/cd/E26576_01/doc.312/e24942/upgrading-legacy-installation.htm#GSUPG00039

Question are: (1) What is "as-install"? There's no such directory as-install\bin in my extracted glassfish4 so I assumed it is the installation directory? Is it glassfish4\bin or glassfish4\glassfish\bin?

(2) I can't see the asupgrade.bat file in my glassfish 4.1 so I'm not able to proceed with the steps on the above link. I'm not sure if the version is related since the document specifically says "upgrade to GlassFish Server 3.1". I can see a pkg directory, and there's also an updatetool.bat. I can't run the upgrade tool though since I'm in a closed environment (no internet).

(3) Is it okay to just delete the Sun folder (for Sun Glassfish Enterprise Server v2.1.1) and replace it with the glassfish4 folder (for Glassfish4.1)? Then I will just run my updated installer that supports the new server. Fresh install works, however we also want to try upgrade.

(4) Assuming #3 is not possible, are there any other way?

Sorry to ask this here since I'm not familiar to any Oracle/Sun community. Google search' top results doesn't specifically answer these questions.

UPDATE: Apparently, I found a similar unanswered thread here: Where is the Glassfish 4 upgrade tool . Same issue, upgradetool is no where to be found. Also, tried to connecting to internet and I still can't update it via updatetool.bat.

UPDATE2: Apparently, updatetool.bat doesn't work for Glassfish4.1. I tried running it/installing it so that the upgradetool might be visible but it seems it can't download the application packages.