You'd want to note that the entire Grotto Spa area is only accessible to adults (age 18). Children may not even enter the area, past the Reception desk. This is lovely for adults, but if you have children with you during your stay and you and DH want time together at the Spa, you will need to plan for them.
To reach the Grotto Spa, you can walk along landscaped paths in the hillside, with views, in the warmer weather. Or you can take interior tunnel corridors, in the cooler weather. It's pretty outside in summer.
While you'll be in the area, check the schedule for the
Biltmore Estate (only a 10 minute drive away from the Grove Park Inn) to see if there are special scheduled events during your visit. The gardens are really gorgeous in the spring & summer. There are many nice walking trails (after touring the mansion). Tour the winery (sample the wines). Some evenings, there are musical performances in this great setting, candlelight tours and lovely decorations during the holidays, and other special events, which may require advance planning (they often sell out).
The lobby of the GPI is "rustic" in a Wilderness Lodge sort of way. There's a high ceiling and a huge stone hearth fireplace, large enough to stand inside when the enormous logs are not lit. The crackling fireplace makes the lobby quite cozy and pleasant in the winter, with gorgeous views of the Asheville area plateau and mountains beyond.
If your trip will be during the Christmas holiday season, there's a giant Christmas tree in the lobby and everything looks very festive. Sometime during the first 2 weeks of December, they host a popular gingerbread village competition. Some folks travel a good distance to compete and/or view the results, which remain on display through the season.
During the warm weather months, a visit to
Cherokee, 1 hour west, is nice, especially touring the Okonoluftee living museum. June brings out the rhododendruns along the Blue Ridge Parkway. Linville Falls and
Grandfather Mountain are beautiful visits - 1.5 hours, winding, scenic drive up the BRP. The Folk Art Center (directly on the BRP) is only 10 minutes north of Asheville, with a terrific gallery of crafts on display and for sale.
Locally in Asheville, there are tons of restaurants, boutiques & shops for browsing. The Grove Park Inn has award-winning restaurants. If you want a fabulous, special dinner outside the Grove Park, try Gabrielle's at The Richmond Hill Inn - pricy but worth it for a special occasion. John Henry's on Haywood St. is popular for brunch. Try the specialty bakery items at the Old Europe Coffee House, near the Flat Iron Building on Battery Pk. The Hop Ice Cream shop offers good homemade ice cream on Merrimon Ave.
Many people enjoy browsing in the newly refurbished, historic Grove Arcade area downtown (near that bakery, above) or in the Biltmore Village (near B. Estate) or in the
Mast General Store on Biltmore Ave. Guess that's enough stuff.

Have a fun stay, if you do decide to visit the Asheville area!