Cultivating a hedge of Bristly Greenbrier below windows and around choke points will prove effective.
Natural razor wire.
http://dendro.cnre.vt.edu/dendrology...eet.cfm?ID=575
Reinforced door jambs with hinge plates at main entries or a door bar can slow dynamic entry.
Sand filled stud spaces around defendable areas.
Sheltered egress should situation go further south.