I'm swapping my sr5 with a 4age and I'm hooking everything up but realize I don't have a fuel return line. Is it necessary? Or can I just block it off and continue with the process ?

Yes it is necessary.

It would be possible to use a completely returnless fuel system from another vehicle but it would be more work if anything.

It's fairly simple to run your own lines from scratch.
I've formed a few brake and fuel lines with very basic tools.
Small pipe cutter.
Flange tool or equivalent.
File.
Magnet can be handy for shavings.
With no bender I've improvised with litely rocking/rolling the line over a large then smaller round surface.
If you can, snag any sizeable of piece of line from a wrecking yard and fit it.
Parts stores like to sell the 3-4ft sections, I like minimal joints. Good luck with the swap.

So If I do decide to make one, where am I gonna lead it to ? I know it starts at the fuel pressure regulater but after that where does it go ?

Heres how to do it with sr5 lines
http://ectoyotas.com/%20forum/viewtopic.php?f=11&t=1344

Ohhhhh okay thanks a lot it helped so much