Yes, a new overnight location could work as it did while you were on holiday.
A 74cm (30 inch) crate is a bit of an in between size, may or may not be big enough for a 6 month bitch. I usually start with a 24 inch (61cm) crate. This does not last for long before I swap for a 36 inch (91cm.) I find the smallest crate, within reason helps with overnight house training. But dogs vary greatly. Before crates became popular My Mandy was clean within a week and away on holiday in a caravan with us within 3 weeks, where Beth took at least 6 months. Since using a crate Amy was clean and lasting all night in 3 days. Chloe took a bit longer taking 5 days. So there you are, less than a week to 6 months, all with the same kind of training. But although Beth took a long time to get the idea, once she did she was 100% for the rest of her life.