PSW expiring, but waiting for sponsorship letter Tier 2!

[NOLAinUK]

I am American and my PSW visa is soon to expire. I planned on applying for a Tier 2 visa through my university, but there has been some red tape with the job and I cannot officially interview for the position until December. Can I leave the UK and come back as a visitor in order to complete the interview process? I will then return to the US and apply for the Tier 2 visa from home...
Does anyone know if I can leave for a weekend and come back as a visitor for 4-6 weeks?
Thanks for your assistance in advance!

[asp]

While you haven't said so I assume you mean that you would be likely to return to the UK for your job interview after your PSW leave has expired.

If that is the case then be frank with the IO on the desk when you ask for entry as a visitor. Explain that you have come to interview for a job that would require you to obtain Tier 2 entry clearance back in the US, you know you can't stay, you know you can't work here anymore, you know you can't switch into Tier 2 in country. Show the IO a return flight booking, though not for too far in the future as there is very little reason why you should need to stay for very long given that you have already seen a lot of the UK.

If you give the IO the slightest cause to suspect that you will attempt to work he will refuse you without right of appeal.

[NOLAinUK]

Yes, that's exactly correct. I would like to leave and come back as a visitor (I am not working presently and have no plans to do so), in order to interview for this position through my interview. Also, yes, I do have a flight booked back to the US in December already.
I just did not know if I there was a specific amount of time that I had to leave for in order to be eligible to return as a visitor.
Also, I understand that Ireland (Republic of/Southern) does not count as 'leaving the country' as it is part of the 'Common Travel Area'. Is this true?
Thanks very much for the info...