Hello,

I am struggling to get any time or money to start working on the outside of my 65 beetle, and without a carport or shed, sits outside in the elements rusting and fading.

Am I better off putting a good coat of Penetrol on the outside, will this slow anything down? Penetrol or another product?

Any advice appreciated.

Depends what you want to do later.
If you love teh patina and plan to protect it over time then use Ankor Wax.
If it litrally is just going to buy you a few years before you blow anotehr coat over it then use Penetrol.
Penetrol actually 'goes off / dryes'. If you are not going bare metal and accidentally miss penatrol it will accept paint.
If you miss ankor wax it won't.

Penatrol makes the surface slightly darker and gives a bit of a wet look.
Ankor wax gives you a really nice satin finish and wet look.