Another club worth a visit if you’re in the North is Sunderland.
I took my lad (just turned 6) to his first match on Boxing Day. He absolutely loved it.
There is a good park and ride scheme – it’s free and drops off/picks up at the ground. Food (for the kids) is relatively cheap and if you are selective about your seats (family area or main stand (expensive though)) there was no problem with sweary types*. The atmosphere was excellent too.
Another option, as mentioned previously, is non-league. I used to be a member at Morecambe when they were in the conference. Matchdays were great. A real intimate family affair. I was on first name terms with Margaret who sold the pies at half time and you could go for a pint after the match with the players in the club bar.
*unlike when I went in the away end at Wigan the other night!