Above weir is a speed limit where you officially need a licence (if you get caught, but the I haven't seen the boat in the last 18 years!) no radio or lights needed, rowing boats everywhere, very few motors other than hired tinnies from the groves. Best place to launch, sandy lane car park and jetty by the dinghy sailing club.
Below the weir is tidal and leads to the Irish sea, though it is past the sewage works, scrap yards and then canalised for 5-8 mile down to parkgate marshes and sandbanks, ie don't bother.
From the weir are the groves, dee bridge, suspension bridge, two water side pubs, the head upriver past the meadows to sandy lane and the dinghy sailing club, then the red house pub, nice! After that is just meadows and fields up through the grosvenor estate to iron bridge about 5 mile upriver.