Hellobee Boards

DD has quiet time in her room or in the playroom.
She's 4 so she stays quiet for as long as I tell her to (1-2 hours).
DS is 2.5 and doesn't stay in his room and doesn't stay quiet so.. I usually lie down in his room with him.

I'd start by identifying the goal, is it quiet time, like he lays down, or is it play by himself in his room time?

If it's play by himself in his room time, maybe put together a few activities that are only for that time, to make them feel special?

DD1 (3 yrs 2 months) has quiet time every day for 1.5 hours. We have a tot clock and she knows she needs to stay in her room until the clock turns yellow - she is very resistant to the idea of having a sleep (even though she does fall asleep about half the time) but if I stress that she can play quietly, so as not to wake her sister, she is fine with that. She has a bookshelf in her room with lots of books, as well as some toys with small pieces that she is not allowed to have out of her room as they may be choking hazard for DD2. She also has a play tent, Fisher Price dollhouse, and some dress up and dolls in her room as well - more than enough to keep her busy but all of them quiet toys.

So far we haven't had any issues with her staying in her room for quiet time and she is usually very quiet in there. I've just recently scaled back the quiet time duration from two hours to 1.5 hrs as she starts nursery in the fall and has a spot in the afternoon class, meaning her afternoon rests are going to disappear

ETA: I do close the door for quiet time, but she also has her door closed every night at bedtime as well so it's not anything unusual.