Help Regarding Necessary Trip During PR Application

Background: US / UK Citizen - applied for Spousal Option October, 2010. My closed work permit (3 year) expired in May, and I have been working assumed status.

My Dilemma: my sister is getting married in the Dominican in Mid August and I would like to go.

I understand that travel is not advised until PR Card is in hand, but in my eyes this is non negotiable. What steps should I take to ensure everything is good for reentry. If they deny me the right to continue work under the terms of original work permit can I enter as a Visitor (Both US and UK are Visa Exempt). If I can't work, not a huge deal while I wait the last couple weeks of the process, I just want to ensure my application does not get canceled.

I was thinking about bringing the following: Receipt for PR and OWP, Printout from ECAS showing application status, (by that date assuming that time-line continues as it has I should have AIP but will not be in the country to get the mail), Letter from my employer stating that my job function / terms are the same.

Anything else I should know / do or be prepared for?

Thanks!