The county's GIS (Geographical Information System) would be the Clark County OpenWeb. Most counties in the US will have their own equivalent to this (for example, here is Nye County's: https://portico.mygisonline.com/html5/?viewer=nyenv), and as far as I know, it is free to use as a source for mapping on OSM as it is government-provided. 99 times out of 100 these maps will be more reliable than Google Maps or any other copyrighted map as the latter will often add fake street/place names to catch users redistributing the data without a license. Unfortunately, when it comes to street view as a source, the biggest three options we could use as mappers on OSM are the two provided in the iD Editor (Mapillary and Bing Streetside) and viewing it in person. Luckily, street view is only important for more meticulous things, and road names can usually easily be obtained through county GIS maps.