also depends on you destination in SD, timing (traffic patterns) and your limitations/preferences
ow rental is usually under 100 and can be much less, uber should be 150-ish ow if dont want to drive; can prob find some sedan transfer ow for 250
if amtrak - uber should not be 70 lax to union station unless some nasty surge pricing; or just do flyaway bus to union station at $7 pp;
noone flies that unless attached to some other segment; if timing is convenient and you are at lax anyway i would consider 7500 pp ow avios redemption perhaps in one direction since it's flexible to cancel