I have a 32ft Heritage Glen 286RL Lite. It travels very well pulled by a Dodge Ram 1500 5.7 Hemi.
If you want an East/West bed, it´s the only one available. 28ft is a bot short for decent living space- we looked at a lot on line and a few at dealers. Really you need to decide how you are going to live with the van and work from there.
The only issue we have is the island sink is too far away from the other kitchen units and gets in the way of viewing the telly from the sofa. The sofabed isn´t comfortable as there is a bar under your hip!
IIRC 28 ft falls into the Euro type of 5th Wheel, so you have a few more options. These are narrower than the American ones, like mine. The more slides you have the better for space inside when parked up.
Again, the van will depend on what truck you get. Euro trucks don´t really have the power to pull a bigger rig, in my opinion.