low budget camera network solutions for Elderly/Widowed

Low budget Camera 10gb ethernet network.  some time additional buildings are 70 yds out from home. need recommended network infrastructure.  Looking at Linux IP cams, Linux NAS unless other solution would be cheapest and best performer. ALSO 2-3 monitor, monitoring.  Continuous feed and some motion set.

in house network and outside network infrastructure as needed.

i will source contributions for each installation..

 12 cams up to 25 cam setups.

full set up recommendations needed.

HUMBLE THANKS