Dan, let me join you in your happiness about getting your "Stream" -- you're in for the "wonderfulest" -- well, sorta!

There has been discussion about toilets that incinerate the waste material, which is then removed via a tray, or drawer, and disposed of as ash.

The other discussion has been about a mascerator but it would require the black water tank

The incinerator has some real possibility but it requires an adequate source of electric power. Not available, if you intend or just might end up doing some boondocking where there is no electric
power.

It is a huge job to install a black water tank, but if you know how to do elemental plumbing, how to handle tools and do some minor metal work (and I seem to remember that you are mechanically gifted), and if you can give the time to do the job, thereby giving up using your "Stream for a while, then why not have at it. That, I think, would be a great source of personal satisfaction.

One further suggestion: when you drop the belly, expect to find some rust which will need to be treated or otherwise dealt with (e.g, welding in new pieces?); you may find some bad wood in the floor from
leaks across the years; and the aluminum belly may very well have suffered electrolysis where riveted to the steel frame members; and finally, consider installing a gray  water tank at the same time.

All of these other items (except the gray water tank) are going to need attention at some time, unless you are very lucky and find no significant rust, no rotten wood, and no scalloped edges (filigree?) on the
belly!

If you can do it, maybe with "a little help from your friends" then go to it. The  alternative is expensive--and you may want to consider taking it to Jim and Sharon Weston to get it done and
over with.

You are going to have fun -- anyhow!

Donald