Bob & Sharon bobojay,
Your long term Sprinter experience was interesting to read. I do wonder if your alignment challenges would have been best addressed by a truck suspension shop, for example the place that took care of our Ford E350 HERE
. They did things that a regular alignment shop would never tackle like changing the bushings from centered to offset to compensate for the extreme circumstances.
About your next rig, possibly a 2100 or 2350 Phoenix Cruiser. I have always thought that if we never towed one of our vehicles, the smaller 5.4L-V8 engine would have been the better choice for our 2350. The V10 does a great job and I cannot complain about having more power, but I feel the V8 would do the job of getting around solo just fine. Under extreme conditions like climbing steep grades, the V8 surely would not do the job as well, but for my wife and I, that condition is not the norm. I'd be fine just taking on those grades a little slower. On the flats, how fast does one in a motor home need to get up to 65 mph? Motor homes in general need to be driven conservatively for safety sake and also for the sake of the occupants, the house, and contents.
I understand that the V8 engine would increase fuel economy by 10% and the purchase price would be reduced by $1000. Less important but worth mentioning is that the V8 offers more room under the hood for mechanical repairs, and the engine weighs less.
The E450 chassis is another debatable subject matter to me. Just keep in mind that the 2100 and the 2350 already have plenty of extra cargo carrying capability, more than you will ever achieve under normal use. The E450's bigger brakes and hydraulic brake booster are surely welcomed, but a rougher ride comes with it. Motor homes get shaken up enough as it is. I would not want to shake up my house any more than necessary. Maybe a leaf spring or two in back could be removed to soften the ride of a 2100/2350 E450. In general, a softer ride is achieved by having the actual load close to the max capability of the chassis. For example, the ride of an empty box truck will jar your body. But load it up and the ride smooths out nicely.
I am not trying to convince you to go with my ideas. Just sharing my thoughts, giving you something to think about. One thing certain, I don't claim to be an expert with these things.