I really don’t understand why some people take the time to answer someone’s concerns with inane, flip answers. I am assuming you are asking the questions because you want to learn so I will give you my opinions backed up by 5 years of RV experience with class A’s both with tag axles and without.
1. Which brands have the best reputation for quality and durability? I'm familiar with Tiffin, Newmar, Country Coach, Winnebago and the older Fleetwood names. I am not familiar with American Coach, Intergra and some others I have seen.
All of the coaches you have listed make high end and low end coaches. If your budget is $200k then you should be looking at a used high end coach. Glitz isn’t the only difference between them. Engine size, transmission, rear radiator v s side radiator, chassis manufacturer, aqua-hot vs water heater, residential vs rv refrigerator, quality furniture and cabinets vs cheap, etc are all things that you need to look at and consider. My first coach was a 97 HR Imperial 40ft with an 8.3l engine and my current coach is a 2005 Safari Panther 42ft with a CAT C13 525hp engine. The differences between the two are night and day. I have the 4000 series Allison (extra heavy duty), 4 slides, aqua hot, residential fridge, all wood cabinets, leather furniture, tag axle and S series Roadmaster chassis.
2. I understand Monaco and Fleetwood are out of business. Would you hesitate to buy one of them?
I purchased my Panther 2 years ago even though Monaco was bankrupt. Monaco still has parts availability and service information for my coach as a matter of fact I am in OR as I am writing this and visited the service center to purchase parts on Tuesday. I purchased my coach based upon the all steel cage construction and the S series chassis with the 10 air bags. I tow a 23ft trailer behind me and just made a trip to Yosemite on curvy winding roads and it was like driving a 65ft BMW.
3. What are the benefits and the downside to a tag axle other than the additional expense?
The tag axle allows the front and rear suspension loading to be changed by adding or removing air pressure to the tag axle. ( rear axle acts as a fulcrum) Adding air to the tag loads the front end and removing air decreases the load. All MH’s should be weighed to determine the proper inflation of the tires to reduce the possibility of overloading the tire and possibly having a blow-out. The tag also makes the coach much more stable in the wind or when driving next to a tractor trailer. The downside is the extra weight, 2 more tires to replace and the loss of storage.
4. What are the major differences between a Spartan and Freightliner chassis?
The best thing you can do is research both chassis and decide which one fits your needs. Don’t forget to research the Roadmaster chassis also.
5. I realize that longer units 40-45' limit your camping choices but I have been told that once you exceed 36' it does make that much difference. Have you found that to be true.
I have had no problem getting my 42ft into any campsite but I don’t boondock often and I always let the park know the size of my rv. I also google earth most locations to make sure there is enough room.
6. Is there significant difference between driving and handling a 36' coach vs a 45' coach?
Once you get used to where the corners are and how to use your mirrors and camera’s there is no real difference. Mine is easy to drive.
6. What are the plus and minuses of towing a toad with a dolly vs something like a Blue Ox with 4 wheels down?
Preference and the ability to have a TOAD that can be towed with 4 wheels down. When I am not using my trailer I tow my Ford Edge using a Blue-Ox tow bar.
7. Is a 2010 Honda accord a viable toad?
I would check Motorhome Magazines Dinghy edition to find that out. Available online.
8. What features do you think would be critical for a full timer that may not be obvious to a newbie? I'm thinking more about things you don't see not features like washer/dryer and dishwasher.
Aqua hot is a must, unlimited hot water for showers and heat. Also a residential refrigerator in my opinion.
9. is there another web site you recommend someone in my position might find helpful?
IRV2.com
10. Are there any brands or models I should avoid?
Just do your homework. Research and test drive before you purchase, take a driving training course if you aren’t comfortable and make sure you have the correct driver’s license classification for your state. (CA requires a non commercial class B over 40ft)Also make sure you have the oil and trans fluid tested by a reputable lab before purchase and have the coach inspected by a qualified RV inspector before purchasing it.
Hope this helps.