Give it time, scottydoc80 - you only posted this last week! Not everyone accesses the site on a daily basis.
For wheel sizes etc. see posts by Vantastic - he listed many details of wheels etc. some time ago.
For accessories, if your Steppy is converted try your 'converter' or any camper supplies shop.
Stepwagon specifics can often be supplied by
www.stepwagon.co.uk - they will advise as well.