"B" loans are a classification of mortgage loans that are available to borrowers with less than good credit ratings. They are also referred to as subprime loans. Different lenders use different criteria to define who is a "B" borrower.
Can an individual with a solid income and good downpayment with a poor credit rating get a loan for a Motorhome?
It may be possible, as the companies that sell the motorhomes often finance the loans themselves. It probably depends on how big a down-payment, how bad your credit is (are you likely to get sued from what is viewed on your report and be under the threat of a garnishment that could make paying your monthly payment a problem). Shop around. The only way to get what you need is to call as many places as you have time to do.