If you opt into the Verizon Global plan, calls are approx $0.99/minute versus around $1.29/minute. And DATA is unlimited. The plan on a pro rata basis replaces your existing plan and costs between $65-69/month. So two weeks would be proportionally part of that and part of your normal plan.
I don't know if verizon needs to be informed if you just use your verizon sim card but it can't hurt.
Use care - folks have occasionally been very surprised by bills...
I am going to Portugal and Spain in October, and already unlocked my Tour with Sprint. I will definitely opt for the prepaid SIM with data (Vodafone, Orange or other) over Sprint's international plan (prorated or not) which offers much steeper voice rates and potential roaming charges that will involve lots of calls to CS later. The question for me is whether the GPS (BB maps, Google maps or other) would work overseas? Google maps doesn't seem to be able to acquire a GPS lock on Sprint Tours using CDMA, but it works fine when switched to GSM mode. Anybody use GPS maps with their Sprint tour overseas yet?