2004 is not too old and the Diplomat from that era was a very solid motorhome, it was the same design for many years and the bugs were out of them. We have a 2004 DP and know many with much older ones. Make sure everything works. At that age the batteries and tires need to have been replaced, if they were not get then handled right after purchase. I would not drive tires that old more than a few miles.

Joan and I bought our 2005 Monaco Knight 3 years ago and haven't looked back. It too had 23K miles. After about a year of weekend camping and a couple of week long trips we decided to go full time. We've been living full time in it for almost 2 years spending last year in Oregon, the winter in Reno/Vegas and this summer in Colorado. There are still day to day maintenance chores, but those you have in any home. We did live in it 6 months before we quit our 'regular' jobs and went on the road...that was the trial run. We've been very happy with the quality of the Knight and would consider purchasing a used Monaco again.

you could spend 10 to 20 k more and buy a newer unit......or you could bank that money and use it to maintain the older unit......either way the same money will be spent new or older to take care of problems as they arise

I'm a gambler, that kind of money set back is a nice cushion and pretty much most coaches have been maintained and have records in the DP class so the homework is already done!!

I've been told more times than I can count that you should budget about $10,000 the first year to repair/upgrade the coach to make it to your needs and wants. A set of tires and batteries can chew up most of that $10,000 very quickly.