I agree, 38 is the best. It will bring you out on the east end of Big Bear. From Ventura use 101, 134, 210 to San Bernardino Avenue, turn left at bottom of ramp onto San Bernardino Avenue, go east to Texas St, turn south to Lugonia, then turn left on Lugonia which will become 38 in Redlands. After the initial pull from Forest Falls it is nearly a straight shot to Onyx Summit and then an easy downhill into Big Bear Lake and Big Bear City.
I don't believe this route is any steeper than 138 and it avoids a longer, more congested route 18 into Big Bear. 38 also avoids a very sharp and narrow right turn over the Big Bear Dam.
Fred & Mary RVM135
2012 Dutch Star 3735 ISL 400
2012 GMC Sierra Ext Cab 4x4