Задала свои вопросы на офиц. мыло. Вот ответ, может кому-то в будущем пригодится такой исчерпывающий ответ:
Regardless to the way you are going to visit the Museum (with or without guide) you must have Entry Pass.
You can make reservation for Entry Passes only via our website: visit.auschwitz.org.
Unfortunately entry passes which are available on online sale are already sold out. The number of Entry Passes on online sell is limited and cannot be increased.
If you would like to join a bigger group (3,5h General tour with educator/guide) or visit on your own, you can also purchase Entry Passes from cashier desks at the visit day but due to huge tourist interest I cannot guarantee that when you arrive at the spot Entry Passes will be still available. I would suggest you coming early.
More information about guided tours you can find at our website:
http://auschwitz.org/en/visiting/guided ... l-visitorsA person who arrives without a booked reservation will be able to enter the Museum. The entry pass will be issued at the visitors’ centre. Entry will only be possible, however, in the first available hour. . During busy periods, this may result in a long waiting time. If you would like to visit the Memorial without a guide you can do it between 7.30 a.m. and 10.00 a.m. or after 4.00 p.m. an you can stay on the grounds of the Museum as long as you wish during the opening hours – that’s not apply in Birkenau. Auschwitz II-Birkenau is accessible for individuals without reservation all day long within its opening hours.
Итог: как и планировала, поедем после 4 вечера. билеты брать в любом случае надо (you must have Entry Pass with or without guide), но после 4 вечера они будут бесплатными, хотя очередей все рано похоже не избежать (During busy periods, this may result in a long waiting time). после оф.ответа теперь спокойнее, попадем мы точно. жаль, что с гидом не получится, но судя по отзывам тут, толпы и беготня только отвлекали.