I'm only a couple of years ahead of you in experience so no sky god but I have managed to fly the 160hp PA28 and various different 172 models. In all cases, it has been either four people, no luggage, 3/4 fuel or only three people.
Runway length is vey important, if you apply the CAA guidance (and the likes of me and you should), the aforesaid 160hp PA28 at MAUW needs on a not very extreme pressure altitude day, 800+m hard or 1100+m grass.
W+B is can kill you and needs careful checking. We normally fly three-up with me in the front and the other two in the back. If we fill the luggage bay, one of them has to sit in front with me.
Finally to support the comments about setting a date, until I got an IMC rating, setting a date for a trip more often than not led to disappointment. Even with the IMCR (not valid in France remember), we don't always get the trip we want. If you want to go on a particular day, plan alternatives in different directions. Cornwall, Wales or Yorkshire could be just as nice.