any one know of a spot in Tralee

I have seen some campers parked at the back of the museum at the end of Denny street.look it up on Google maps.there were no overnight parking signs the light poles.I wouldn't recommend there with small kids.

Have a look at "our lady's and St Brendan's church".I saw a camper in the car park there
Its about 10-15 mins from Denny street

Both of the above are only suggestions.
I haven't come across anywhere that would be ideal in Tralee.

manor would be fine but I would have thought that it was too far out for you.
it is walkable but 3 km and 35 minutes of a walk going by google maps.
the big problem is getting suitable parking in daytime in Tralee centre where you will fit.
I parked on the roadside outside the greyhound stadium on brewery road its right next to the church I posted before

the parking spaces in manor are quite small for a car but if you decide to go there, check behind where Halfords and petmania are in the retail park there is loads of room there and you are out of the main part of the carpark.
again use streetview to check this.

actually look behind mothercare in manor on streetview.there is nice space there.
its definitely quieter there than the main carpark