We prefer 99. The Lakes in Chowchilla was very nice when we were there about a decade ago. The town is not. Bakersfield has a number of good parks. The two previously mentioned rest stops were closed last week when we drove thru. As far as 5 goes, Almond Tree & Kitt Fox are ok for overnighting. We frequent Flag City. It's Passport America weekdays I believe. We've stayed at Expo, prefer Mark J. It's adults only. Check reviews at one of the RV park review websites.
Both 5 & 99 have horribly rough road conditions in places. Around Stockton on 5 was absolutely the worst when we traveled it last Fall.