The time is September 1997. Rock Prairie has just recently or is in the process of extending from the stub where it abruptly dead-ended at Victoria Avenue all the way to Wellborn Road. Using the rural back road of North Graham Road was about to end, and in February 1998, a railroad crossing connecting Gandy Road and Rock Prairie Road was approved. It was this time that Alta Vista opened at 3110 Gandy Road.
The Rock Prairie extension only had a street sign (Wellborn/Rock Prairie Road) and a stop sign (along with a new Exxon station that opened, which included an A&W). Beyond the railroad was a dusty road ending at a yield sign, and that was Gandy Road. Though a dusty, rural road, it included the Diamond T Stables (still with "3270 Gandy", which remained on the sign until it was eventually sold to developers and torn down), some sort of facility that looked like a fish farm or water retention (little ponds in the back), and Alta Vista Christian Academy.
My only experiences of Alta Vista came from exploring the new extension of Rock Prairie after it opened circa 2000-2001. The new extension was fascinating: there was a dip in the railroad crossing (as opposed to the "humps" in the others): this was taken out when they expanded Wellborn Road. In the early days of the crossing (circa 2001, I believe), there was a four-way stop at Old Wellborn, and several country-oriented places along the way: including aforementioned Diamond T Stables, the adjacent Diamond T Storage (now Tex Storage), and of course Alta Vista (a small private school). The new extension went all the way to North Dowling, and then, on the other side, Blue Ridge Drive, which went even further.
Of course, all that began to change as urbanization slowly crept west. Alta Vista struggled for years, even having to be saved from bankruptcy in the early 2000s thanks to donations, but by the mid-2000s, Alta Vista had folded up and disappeared, with no trace remaining. It's now the Williams Gate subdivision.
As an aside, I remember how the old railroad ROW looked in 2001 (now the intersection of Holleman and Rock Prairie): it was a sad, gated-off place that was kind of creepy-looking due to the overgrowth, with the (patchy) I&GN Road going the other way. That was the original ending of Gandy (it curved into I&GN). The rest of the way has the partially-undeveloped Great Oaks Estates, farmland, and another trailer park (substantially less attractive than the ones closer to the old ROW). Today, that intersection is a stoplight with concrete and four lanes in all directions.