Need help staying out of bed during the day

BD and I have decided to live together starting January 2018. He has two kids (5 and 8). BD has the kids part time. In the past I’ve stayed over when the kids were there and I have had difficulty finding things to do while the kids are there. It’s a very small house (2 bed rooms 1 bathroom) so we have very limited space. This usually leads to me just lying in bed on my phone because the tv and pc and the living room are all taken by the kids. This is a problem however because the 8 year old has noticed I spend a lot of time in bed but even if I’m doing something productive in bed, the 8 year old doesn’t know that. The 8 year old just sees a person in bed being lazy.

I’d like to be a good role model to both the kids. How do I stay out of bed without just aimlessly walking around?