Welcome to AAM
I dont think you should bury your head-the problem won't go away! You will not get advice here on how to avoid anything that is due. (Option 2 is making a false declaration and is, in itself an offence)
The non-registration with the PRTB is actually going to be the biggest contributor to your tax bill. (non registration means you cant write off the interest on the loan) So, unless you have loads of other expenses, practically all your rental income is taxable. If you don't have the knowledge to correct your affairs yourself, you will need to consult an accountant. In any event, I recomend you do consult one.
However, if your financial situation is already bad-i.e. Large outstanding mortgage, arrears, negative equity, other loans etc., you may be a candidate for Bankrupcy or a Debt Settlement Agreement in the UK. Much more information on your financial situation would be required to give a considered view on that.
To sum up, it's best to get your tax affairs in order, and then if you can't pay, consider your options. Revenue may accept installments.
I am sure others will post along the same lines as above, but hopefully you will get more advice on your overall debt situation and how best to proceed.
Best of luck with what ever you decide to do.