Despite being listed as harder by the start screen, I find the Von Carstein may actually be easier than the regular Vampire Counts. Foremost among the reasons is not having to wipe out the Dwarfs. It might be best to go for a Short campaign victory for the sake of your sanity.
Question for the longer term, my plan after doing chaos is to do white drawf camapign to do his quest line but not the full camapign but then do I do mini camapigns or main camapigns first for elves and beastmen? I get the impression full camapign?
The beastmen mini is the same general game as their grand campaign, but with less enemy variety (basically only Empire--there's other Beastmen and Greenskins but they won't bother you) and very passive AI--unless you start a war the AI only declares on you when scripted to. Only real reason to play it is unlocking Boris Todbringer for custom battle.
The Wood Elf campaign is different. Unlike the grand campaign they have normal-sized settlements across a map instead of a few huge ones and a bunch of tiny outposts. It also starts out with a ton of razed settlements. I think it was generally regarded as a big improvement over the beastmen one.