Fumbled Serve
 

After the R beckons for serve, S1 fumbles the ball, which rolls into the court. (Anything, yet?) S1 runs on the court, recovers the ball (does it matter if a teammate helps or recovers the ball and throws it back to S1?), returns behind the end line, and tosses the ball and lets it fall--all before the 5-seconds has elapsed. The R rules a replay/re-serve. Correct ruling?

Not in NCAA-W, but I'm quite sure that's not the ruleset you're discussing. (And I can't help with other rulesets.)

Yes -- this was HS -- but what is the NCAAW ruling?

For NHFS rules: the server gets a re-serve unless this is the second re-serve in this term of service.
For NCCA-W rules: the server does not get a re-serve attempt.

Not sure I'd go with re-serve here in NFHS. A fumbled/lost ball isn't the same as a dropped toss for service.

If they get it back within the five seconds and serve, play on. If not, LOR.

Per the NFHS Casebook:

8.1.6 Situation B: After the first referee's signal for serve, the server: (a) swings and misses the tossed ball; (b)swings, misses and the ball contacts her shoulder; (c) lets the tossed ball drop to the floor; (d) catches a bad toss; (e) tosses the ball, then lets it drop without swinging at it, but it touches the server's knee as it drops to the floor. Ruling: (a), (c), (d), and (e) re-serve; (b) illegal serve, point/loss of rally. Comment: in (b), if the ball had not been touched the server, but dropped to the floor, it would have been a re-serve; (e) no attempt was made to serve the ball.

Right. The server did item (c), but did so after fumbling the ball, chasing it into the court, and returning to the service area. Does any of the "fumbla, chase, return" action affect anything?

I didn't think so, so I didn't call anything (well, except the re-serve), but I thought it was worth discussing here.

After reviewing Rule 8, there is nothing in the verbiage of the rule book or the case book that provides for an illegal serve ruling when a player crosses the line. Bold/underline emphasis mine...

Rule 8-1-2 . . . The server shall serve from within the serving area (2-1-6) and shall not touch the end line or the floor outside the lines marking the width of the serving area at the instant the ball is contacted for the serve. The server's body may be in the air over or beyond the serving area boundary lines, having left the floor from within the serving area.

In this case, as long as the player is in the service area at the moment of contact (or, by implication, toss for service), all is good.

Nope, not illegal unless ball is contacted when the player was last contacting in bounds, basically. You can certainly drop a service toss while over the line.