My basic question is there a simple way to pass 1500 form variables from one page to another?

Far from being an expert in these matters, but AIUI a POST does not have any limitation in this sense. What's the problem?

I understand the idea behind "don't reinvent the wheel" But currently I cannot use any modules as "I can't" install them.

Indeed you "can't", but you can, especially if they're pure Perl: otherwise yes, you may have some troubles.