[R] newly install old and present R versions

[Thomas Mang]

Hi,

Moving to a new computer (Windows 7) but for reasons of reproduceability 
I would seriously like to also install my present R 2.8.1 along with all 
extension packages on that machine as well (that is besides R 2.14.1).

What's the best way of doing so?

My idea is:
Get the setup for 2.8.1 and install it; during install neither select 
'save version number in registry' nor 'associate Rdata files' to keep 
the registry clean.
Manually Copy the extenxion packages from my present machine to the lib 
folder of 2.8.1
That should mean 2.8.1 should run.

Then install 2.14.1 and download most up-to-date versions of packages.
How do i detect if packages were e.g. renamed or merged? Also manually 
copying my old packages to the lib dir and then running 
update.packages(checkBuilt=TRUE, ask=FALSE)? Will that work under these 
circumstances as well?

To make things more complicated I am also using Rtools. Is it possible 
to have two parallel versions of Rtools? Sure I can install it but I 
suppose as it sets some PATH variables only one can actually only be 
active at a time. Hence it might be smarter to avoid installing Rtools 
for 2.8.1 alltogether, that is live without it (having enough troubles 
with running Rtools for one version alongside with MinGW as also the 
path to g++ can conflict ...)

thanks,
Thomas