Here are some routes from Duck Pass to Iva Bell hot springs via Duck Pass and Purple Lake. It appears that once you get to Cascade Canyon there are two routes over the ridge to get to Iva Bell, one going north on the east side of Fish Creek then crossing and cutting back to Iva Bell. The other goes south and west along Minnow Creek over the ridge then cuts north to Iva Bell. The Fish Creek route seems shorter with less vertical.