Without a doubt, you have described the Ruger 10-22 for your requirements.
* Target shooting/plinking
* Easy to upgrade
* Iron sights as well as optics
As a previous poster mentioned, he has seen more 10-22's than all the others combined, and I would agree with him. (The perfect budget Appleseed rifle imo) They are very reliable little rifles, and tons of fun for the whole family right out of the box. The only limits when it comes to mods is one's own imagination.
The 10-22 also makes for a decent little rifle for introducing other folks who are new to shooting...... especially the youngins, provided the proper fundamentals of safe handling of firearms, and marksmanship is applied as well as supervision by a capable/responsible person.
Mine are all stock as far as "internal parts" go, and usually add either/or peep sights/optics, as well as a sling. Also use them for small game hunting, and as a simple tool around my property.
My preference runs towards the simple/ reliable factory 10rd flush fit rotary mags for a "farm implement", as the feeding system is very well protected from hard use and not so perfect conditions of transport.
I have always wanted to go nuts with one, but my M14 habit takes precedence over anything chambered in 22lr.
....or any other firearm for that matter.
I'm still having fun with them as is for now anyways. A sling, a few mags per 10-22, and ammo for a fun day at the range with the grandkids. As it was with my kids, they can also earn the right to keep it for themselves.
Contrary to the opinions of a few others, I do not agree that the 10-22 "must" have "X" amount of $$ worth of upgrades to be ....well...whatever.....
I have owned them for years and do not find it necessary to buy anything other than ammo for them. My mods( sling/peep sights/optics) are simply a personal preference.
Whatever you decide to buy, I would recommend you take it to an Appleseed event. All of the instructors I have met were all very friendly folks who love to share their knowledge with others. Young and old alike
It's a 22lr rifle, so have fun with it and stay safe.
11B