I use Locus Maps with things like that. On my request, menion (the author) implemented support for full offline
.kmz – i.e. the
.kmz files can be self-contained, including everything like images etc., and then are available with all their data, not requiring any network connection. That's an ideal thing to create your own travel guide, which I did a couple of times.
There are several addons available for Locus Maps, a.o. an "Augmented Reality" addon – which can be used to see in which direction there might be something interesting which you "bookmarked" (have an entry in one of your
.kmz files) – in your case this can be handy when checking what's in sight, visually.
Locus Maps: Ranges, NAvigation, Compass (source: Google Play; click images for larger variants)
Pretty good support, regular updates, privacy-first (if you want to navigate your contacts, you either have to enter their addresses manually, or need a separate addon – Locus Maps itself avoids requesting permissions with privacy concerns). Supports a range of features by itself, like Navigation, Geocaching, and much more. You can create your own waypoints, and later export them as
.kml (or your track as
.gpx) – a feature you might welcome when walking your boundaries.