Santa Fe is one of the world's great travel destinations and is only about 35 miles 55 km away by road. It would be silly to make a vacation stop to see Los Alamos and not see Santa Fe.
Taos, another fine travel destination, is a little over an hour away. Retrace your path down NM 502, but before reaching Pojoaque, turn off on NM 30 to Española by way of Santa Clara Pueblo. NM 30 leads you to NM 68 and eventually Taos via a beautiful drive along the Rio Grande. Or, take the "high road" to Taos through a series of tiny Colonial Spanish mountain villages.
If traveling to Albuquerque on the way home from Los Alamos, consider forsaking the highway route NM 502 to US 84/285 to I-25 in favor of the "back road" through the Jemez Mountains. Take NM 501 west out of Los Alamos and proceed past the Camp May road to a T intersection with NM 4. Left leads back to Bandelier; instead turn right, climbing steeply and spectacularly into the mountains and through Valle Grande, the largest grass meadow of the Valles Caldera. On emerging on the west side of the mountains, NM 4 connects with NM 44 US highway 550 which leads back to the interstate close to Albuquerque. This takes up to half an hour longer than the highway route but is worth it for the mountain scenery. Be wary of radar traps, and skip it in winter after a snowstorm, as the road through the mountains may be temporarily impassable.