im FULLY supportive of not letting her cry, if thats what your heart and your instincts tell you to do! :) :) you go mom!! :) :) thats the best thing; just listen to your heart.
there was recently a blog posted about increasers and releasers. it basically said some babies cry to release stress, and they are asleep like a minute later. these babies we can let fuss for a FEW MINUTES because thats simply what they need. they will fuss and fuss in your arms, but they will go right to sleep in a moment after you lay them down and let them fuss for literally, less than 5 minutes.
other babies are increasers. the more they cry, the more they cry. and the louder they cry. it increases. these are babies that should NOT be left to cry, and do NOT respond well to any methods. just follow your instincts.
i dont know how you are feeding baby, but its likely that shes hungry. ALSO; shes lonely! she misses you at night. dont feel bad if you have to bring her into your room or something. your kid wont be sleeping with you when she graduates, so just calm yourself and figure out what your child needs, and what works best for you. for me, we only have a double wide, but even walking down the hall in the middle of the night was annoying. so our son just slept in the same room as us in his crib until he was almost 3, but now sometimes he does come in and sleep on blankets on the floor. trust me, its only a short period of your and your child's life. and its also much safer; babies who sleep near their parents have a HUGE reduction in the risk of SIDS, simply because of the mutual ability to hear each other.
also remember; babies who wake often have a reduced risk of SIDS as well. ;) simply because they are waking. babies are actually programmed to wake often. its the ones who sleep too deep for too long you have to worry about! !
anyway, try to see if shes hungry. its likely she is, especially at the 4 month and the 6 month mark. babies tummy is the size of her fist, and shes going to double her height and triple her weight in a year! this is (hopefully) the ONLY time in her life this is going to happen, so it requires a lot of feeding! :)
anyway good luck and listen to your instincts, not a book, friend, parent, inlaw or even doctor. you are the mom and you have to parent the way you feel is best for your baby and your family :)