I'm looking for a romantic getaway over 4th of July weekend to celebrate my wife's birthday. We'd want a direct flight from Vegas, something within 2 hours or so. Quiet, secluded, and with a great pool
Carmel-by-the-Sea deserves serious consideration here. It's a quick, easy flight from Vegas, the weather in early July is genuinely lovely (cool mornings, warm afternoons, no desert heat), and the whole town is built for exactly the kind of slow, unhurried romantic escape you're describing. The coastline around 17-Mile Drive and Point Lobos is legitimately stunning, and there's enough good food and wine to fill a long weekend without any effort.
For where to stay, Bernardus Lodge in Carley Valley is the move. It's about 20 minutes inland from Carmel proper, sitting in the middle of wine country, and it has one of the best pools in the region, warm, uncrowded, and surrounded by vineyards. The spa is excellent, the restaurant is taken seriously, and the whole property has that rare quality of feeling genuinely secluded without being inconvenient. This is the kind of place where a long afternoon by the pool with a bottle of local Pinot doesn't feel indulgent, it feels correct. Villa Mara, closer to downtown Carmel and the beach, is a strong alternative if you want to be walkable to the village and shoreline, it punches well above its price point on hospitality and gets criminally little attention.
Post Ranch Inn in Big Sur is the other obvious answer and it's genuinely one of the great romantic hotels in America, cliffside infinity pool, no children under 18, extraordinary views, and a restaurant worth the drive on its own. Big Sur is only about 45 minutes from Monterey airport, so if you can get a direct Vegas-to-Monterey flight (United runs them), that whole area opens up nicely. Post Ranch is a true splurge, but for a milestone birthday weekend, it's the kind of place that earns it.
One practical note: July 4th weekend is peak season for both areas, so whatever you book, book it now. Bernardus and Post Ranch in particular fill up fast around holidays, and you don't want to be left choosing between whatever's left.