Thanks Frazieme,
We just want to accelerate the process as much as possible, so we will try to submit all the visa things and then snatch some time for holidays.
When you say that after biometrics we have 5 days, do you mean 5 days to send off the documents with the VFS courier? That shouldn't be problem if we have all our documents ready in advance, should it?
The documents you need to send off include the applicants passport, which is what Frazieme was alluding to.
Unless you're doing a domestic holiday, that would throw a spanner in the works.
If you're going on a honeymoon outside the US, you really should wait until your back to hit 'apply' in the online app. Once you submit it and have attended biometrics, you've got 5 days to send off your docs, including the applicants passport, to UKVI.
Biometrics appointments are usually readily available. Why not get married, honeymoon, submit app, do biometrics and then send everything, including passport, off.
If you're really in a rush, have you considered applying priority? I think putting the money toward priority now or toward an in-person appointment in the future would be better value for money than the third party marriage licence.