I'd follow my transfer guide, it's the most complete one can get a backup; a lot of hosts advise using control panels and such but I've never found a full solution that really works short of getting in there and doing it yourself...

As for moving the domain you could do a couple of things; your account at Interserver has its own DNS management system in the billing area, you can just set your domain records there and use their DNS servers or you could use a 3rd party one, or you could setup a DNS server on your VPS (which I'd generally advise against), or you could use a CDN (such as CloudFlare which has a free option) to host your DNS or as a full CDN solution.

Another route you could do would be to hire out to get everything moved and settled at its new home.

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
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