Venus and a Boundary Setting Opportunity: Advice Needed

Things have obviously been rocky between Venus and DH/myself but DH has been doing his best to maintain a healthy relationship with Venus and FIL. Although I am NC with his family, DH is not at that point yet and I support his decision. We have a relatively light responsibility load going into this weekend so we thought that it would be a good time to take a day trip to his hometown (I will be visiting my friends there, not his parents). Without going into too much detail, DH and I are extremely busy between full time work, part time grad school, and volunteering so it is a big deal for us to spend a full day away. DH is requesting advice from you guys on how to reply to this latest text exchange between him and Venus:

DH: Hey, I wanted to see if you guys would be around this weekend. I'm free and was thinking about making the trek up to visit.

Venus: Hey! Yes we will be here and would love to see you.

DH: OK, I will plan on showing up between eleven and noon on Saturday :)

Venus: So you're only coming for part of a day? I thought at least you would spend the weekend. But I'm grateful for whatever.

DH: Yeah, classes have already started and a day trip is what I have time for. Sounds like you're trying to guilt me.

Venus: Don't you feel even a little guilty?

DH wants to use his reply as an attempt to set healthy boundaries. We considered the whole "no is a full sentence" idea but he would prefer to try to explain/enforce the boundary (I know, I know, don't JADE...I have tried telling him about that but he isn't willing to hear it from me at this point). Any advice you guys have for an appropriate reply would be very much appreciated!

Edit: Thank y'all so much for your responses! They sparked a constructive conversation between DH and myself...which is sometimes challenging to do with such an emotional topic. While DH did not use any of your responses verbatim, your input definitely helped him push back harder than he otherwise would have. Baby steps....

DH's reply: "I'm setting aside time to spend with you. Why should I feel guilty about that?"

Edit2: see update here