QUOTE (Kathryn41 @ Jul 21 2008, 09:19 PM)

Yes, being able to visit while a K-1, K-3 and CR-1 are in process depends very much on the country where the beneficiary lives. If she is in a First World country she should have no problems. If she is in a third world country, it would be unlikely she could get a visitor's visa even if she wasn't married or engaged. If you provide more information about your specific circumstances we can give you a more specific answer.
Worse case scenario if you choose to use a K-1 and wait until the 90th day to get married, then apply for AOS and the AP, it is conceivable she would not be able to leave the country for upward of 6 or more months. If, however, you get married the day she arrives - or day after to let her catch her breath - (legal court house wedding is all that is required), and apply for AOS and AP the following day, she would likely have the AP within 3 months. As well, once she files the AP, if there is a life or death emergency back home and she has already filed, she can go to the local USCIS with proof of her filing, and evidence of the life or death situation back home and ask for an Emergency AP. Depending on the day of the week and time of day, they can generally get that in 24 to 48 hours, although longer over a weekend.
If there is a likelihood of someone falling ill and dying in the immediate future you would be better served getting married overseas and filing for either a K-3 or a CR-1. Depending on what country she is from, she may or may not be able to visit while she waits. You, however, can always visit her. If she is able to visit during a K-1, she would be able to visit during a K-3 and a CR-1 process as well. If she can't visit during the K-3 or CR-1 process, then it is unlikely she would be allowed to visit during a K-1. Whatever choice you make will require some waiting and time apart. Choose what is best for your own personal situation.
Just one more thing I would like to add is that if your SO enters with a K-1 visa and has to leave right away the consolate can issue another K-1 visa as long as it is within the original 90 day period that the first one was issued. It is up to the CO discretion.