I have no experience with this, as Honey joined the household Saturday, but here is a quote & a paraphrase that seem useful:
The Rabbit Handbook pg 34: "The spot-on product Advantage has tested safe for rabbits. ... Small rabbits should be treated with half a prefilled tube labeled for cats. Large rabbits can be treated with a full cat dose. ... Some vets have used Program at one half to a full cat dose. ... This product can be used concomitantly with Advantage. NOTE Unfortunately, many flea products labeled 'all natural' or 'organic' contain products such as pennyroyal that are toxic to rabbits."
Rabbit Health in the 21st Century, pg 53, mentions Advantage & Program, then says Frontline & Sentinal should not be used. For treating the environment use a boric acid product such as Flea Busters on the carpet once a year. Common table salt on the carpet dries out the fleas, but must be reapplied after each vacuuming. It says to clean washable surfaces with Murphy's Oil Soap, which repels fleas. Wash everything you can in hot soapy water.