The Archive at Trebon (for South Bohemia) allows private individuals to research there. Some of my distant relatives who live in Austria go there, but have had to make their appointments farther in advance than they used to have to do. You need to know the hours of the archive, and reserve your place ahead of time, there are a limited number of spaces (and hours). They do not speak Czech either, but of course carry little charts and books for the names of villages in the 2 languages. I, too, feel frustrated that I cannot explore so many collateral lines as I would like, but by reconnecting with my relatives in Europe, have gained so much beyond what my researchers have obtained. Linda