I've included some links to some of the largest monasteries in the USA, the Hsi Lai Temple the headquarters in the USA for Fo Guang Shan which was founded by Ven. Master Hsing Yun, who promotes traditional Vinaya Sangha and new school called Humanistic Buddhism, it's a very large group that has temples everywhere in the USA. Very good group and well-trained. Great at large crowds and attracts large crowds, lovely tea houses, active well educated and nice Sangha largely bhikshuni and some bhikshu. This is a closed community to outside Sangha, however, if you choose to pursue residency be warned you more often are asked to return to lay life and apply to them for monastic training.
Bhikshuni be warned in the Chinese Buddhist Bhikshuni Sangha it is not normal to return to lay life and expect that you will be accepted again even if you are told to do this, just don't. Many women are treated harshly by resident bhikshuni who try this, most if not all fail and only achieve novice status. I strongly do not recommend anyone doing this at all. I am hoping one day that tolerance for outside traditions and recognition of full ordination of monastics who want to reside within their Sangha will be in their future. Sangha outside their FGS system may visit for very short stays, you will find them friendly and very nice. I count them as my long time friends and ally's.
I've also included the Sagely City of 10,000 Buddhas a totally friendly group of orthodox 2-part Sangha which observes additional teachings of wearing the work robe (5 strip) and the strict segregation of genders on their very large monastery grounds.Everyone there speaks English and it's known for tolerance of both Theravada and Mahayana schools in residence. This is a closed community. Ven. Master Hsua Hua donated the land for the Theravada monks of the Abhayagiri Monastery to be built and reside. Limits outside Sangha residence to short, very short stays. One day they hope to have enough housing for visiting Sangha who wish to apply for long term stays.
Chuang Yen Monastery, the visiting monastic by policy. This place has provisions for allowable with permission a 2 week stay at the longest which is unfortunately very, very short. But historically this has served it's purpose as a wandering monastics way place. Very nice area, remote but they have active amount of laity and very good Sangha in residence.
If there are any communities that have open doors to outside Sangha then let us know, it will be shouted from the rooftops (not literally but we will post links or information).