You should Probably start at the wall

That wall could help you both guard your possessions and your life from any and all who want to attack you. The wall will have to be both lumber and steel based on the fact that these infected are a lot tougher and stronger than a normal person. Also it looks like that possibly some of the infected could just climb the wall. Another problem for this is those huge breeders that could just smash right through. Hopefully the infected leave you alone until you can at least get the important buildings protected with the wall.

Thankfully for the huge amount of scrap that you kept from both those car bodies and airplane parts. The fact that you are also in a forest should help you build the wall both strong and thick enough to survive for a time. This will take you a week or two to do it alone but maybe you could convince some people to help build this wall. You could possibly pay them with food or even information about the forest and where not to go. Or you could give them a place to sleep when needed or if they are trying to escape people or infected.

It might be a good idea to either get a few people or none at all to live with you. It also seems that you will need to plant more food and forget about a lot of the luxuries that you had. The help could help you get more done and help defend said wall a lot easier. The one downside is that the more people living with you equals more infected that are in each possible attack. So should you live alone? Should you help some people? Or do you set up policies for anyone staying or visiting?