mmm,
Sorry - you can hide the login to register - but guest (form)? that I'm sure can be done by hacking the code or // hiding the address - ?
the only thing by doing that is that you will have no - invoices, stock control, emails- confirmation , no shipping or postal will be possible as they are calculated all based upon- the address Types into VM - yes you can get to paypal and put the address there but that will not flow back to VM without guest registration.
So add a product to the cart and jump to paypal - and configure shipping - at the cost of the product?