There isn't much in it really - if you do out-land the whole process might be finished in 5-6 months (London is pretty quick) but you may well have to go back for an interview and at the very least you will have to go out of the country so that you can come back in and "land".
If you apply in-land you will probably have Approval in Principle (AIP) in 6-7 months but you have the option of applying for an Open Work Permit (OWP) at the same time. This would mean that when AIP is granted you could be able to work here - I realise you say money isn't an issue but boredom might be!
Either way you should remain in status while you are here - it is possible to extend your visitor visa from within Canada, the information you need is here
http://www.cic.gc.ca/english/visit/extend-stay.asp.
Thaiguy is right though, if money isn't an issue you should probably go ahead and do in-land if your main goal is to stay together.
I'd suggest you go to the CIC website and read through the forms and guides to see what's required. There's a lot to do (obtain police checks, medical exam, gather all your evidence, complete the forms) to see how long it might take you to get it all done and if you have everything you need with you.