Optics enable you to study objects of interest from a distance without necessitating movement or revealing your presence. A quality spotting scope of 60mm objective or larger will allow intense study of an object from moderate to far distance. With a Kowa TS13 angle head 60mm scope fitted with variable 20-60x eyepiece I've watched mountainsheep at a distance of over 5mi... Not like you could discern excellent detail at the distance, but I was able to get an idea about horn length on the rams and tell lambs from ewes. Of course, this was on a sunlit mountain meadow and the white wool contrasted well. The low-end Kowa was not able to resolve at higher power than about 30 or 35x, but for a lap-cradled observation at such distance the compact and lightweight 613 was very good.
I've since upgraded to a Fujinon 60mm and find the larger diameter eyepiece resolves far better in shadow and does not degrade as severely at distance when higher limit magnification is engaged. The scope is significantly better while remaining light, compact and a strong bargain among lower priced quality scopes. Again, I like the angle-head design. The 45deg angle enables much more versatility when used from tripod for aerial observation and can be employed around corners or over cover if your position allows.
A spotting scope is best used from a tripod. As a shooting aid, the tripod should be capable of setting-up in low enough position to allow a prone shooter to roll on their side without significant shift of position. This takes a special shooting tripod or a pro-quality tool which has legs that extend almost flat. A hunter can use their scope rested on a daypack. A 45deg angled scope can be used cradled in the lap fairly effectively. For still-hunting and general woods walking, I carry an older Redfield scope on a strap around my neck. The armored scope is light enough to not fatigue but is instantly available to checkout distant objects or areas for reconnoiter.
Plenty of fine spotting scopes out there. Zeiss, Swarovski, Leica, Fujinon, Pentax, Kowa, and Nikon are among the finest. The older Redfield armored spotter kits which include fixed and variable eyepieces, shooter's tripod and carry case are often available in as-new used condition. They are a fine choice as are the various Bushnell Spacemaster spotting scopes.
Might give some thought to digi-scoping. This is the hobby of wildlife and other outdoor digital photography using a quality spotting scope in place of a large tele-photo lens. Having pictorial record of areas around you could be a great asset. Combine digital photos with topo map of 1:250k inch scale for critical areas of your surroundings and you have some excellent resources for planning and prediction.
Costs: A used Bushnell Spacemaster is a fine optic. Likely find one on Ebay or maybe in a pawnshop for $200 or less. The Redfield kits are in the $300+ range depending upon condition and completeness of kit. Older Kowa models like the 611/613 have been superseded, so may find a bargain, but these are worth the $400 you'll usually find them offered for. Any Zeiss, Swaro, or Leitz product will be superb, if only for the superior contrast and tonal control their lens systems feature. All the Japanese camera-makers that offer spotting scopes make a fine product. I gave Fujinon a try because I already owned a set of surplus M22 mil-spec 7x50 binoculars which are superb. The Super 60 has been better than I could have hoped for.
Observation is a critical skill for the Survivalist. Being cautious and avoiding trouble is the intelligent solution to situations that might be confrontational or violent. Being located Out Of The Line Of Fire has so many advantages; keeping out of the line of fire also will pay dividends.
A 60mm or larger objective is a big lens that will reflect sunlight, so... a lens hood may be critical to avoid giving notice to the whole world where you are. Many scopes have a built-in sunshade, but if observing almost directly into the sun, you may need a much longer tube to avoid reflection. Might also obtain screw-in filters like a polarizer or deep red photo filter for special situations. A cardboard tube or rolled sheet of construction paper can be improvised for a longer tube; perhaps even a very thin-walled section of plastic pipe. There are also special non-reflective honeycomb grid pattern diffusers which maybe accessories your scope mfr offers.
More to come on subject of binoculars and riflescopes.