ExBF and I had a 21' Amerilite that was OK lengthwise, but the downside was the inability to get past each other in the middle. It had a mid-kitchen, end bathroom so if someone was getting a drink or making a sandwich, they had to squeeze past the other to get to the bathroom. If you are the kind of person who is bothered by that, be sure to get a slide for the extra width.
In that size trailer there is only the dinette for sitting and one bed for sleeping. So think about where the dogs will lay/sleep.
He later bought a 26' that had no slide still, but the bedroom had a door and there was a small sofa. That allowed a little bit more space but the width was still an issue (for him, didn't bother me.)
Definitely do not get a corner or crossways bed for 2 people to share. One of you won't be able to get up without climbing over the other.
You also will need a spot for food/water bowls; you cannot leave them outside.
Anything longer than 26' is going to be a tighter fit in many sites. So if you like older campgrounds with mostly smaller sites, stick with short.
I would not get bunks if you don't need them for kids, unless your dogs would sleep on the lower one. You could use the upper for storage. You could also remove the lower bunk and use the space for dog crates, if you travel with them.