When my T was away for 5-6 months, I decided I was going to write a book for her. When she returned we were going to be starting on termination work for the last six+ months so I decided I'd do a story of my life in therapy (since I was 20), a novel. I didn't at that time (have since, a few years ago) but the thinking about it and planning it, etc. was very helpful for me while she was away. It helped me better connect to how I understood myself and therapy and my T, etc. My novel I finally wrote had T sessions in it but the whole exercise was really good for me, helped me a lot while she was away.

Could you think of and do a big project like that that the little ones could help with (maybe by illustrating?); a kind of diary for T so that when she does come back you'd have a "book" to give her that would catch her up and tell her things you haven't been able to tell her while she's away because of no privacy, etc.? Maybe a book of poems or short stories, or essays. . .