I would say no, LABs do not cover the land based highlights, but rather offer only 2 visits on their itineraries. Yes, Bartolome is a highlight, an iconic site that it is the most photographed site in the Galapagos (from atop). A huge highlight for someone who is not traveling out to Isabela is snorkeling Bartolome with penguins. N. Seymour is great for nesting blue-footed boobies and frigates as well as land iguanas. All boats visit either the Darwin Station (Santa Cruz) or the Interpretation Center (San Cristobal). These are open for anyone to visit as Dom pointed out.
The non-dive visits at National Park sites are:
Aggressors: N. Seymour and Bartolome.
Deep Blue: N. Seymour and Sullivan Bay. Bartolome snorkel.
Galapagos Sky: Bartolome land visit/snorkel and Santiago.
Wikipedia does a fairly decent job of describing the various visits in Galapagos.
An option I would highly recommend if you don't want to do two cruises is to go diving on a live-aboard and then head over to Isla Isabela for a few days.
Isabela is such a beautiful, sleepy fishing village that has sandy streets, crooked tree trunk light posts, 2 resident diving soon-to-be-if-not-already legends (Mathias Espinosa and Pierre Constant) and there's even great food. The water is stunning and you usually see penguins upon arrival. You get get there by public boat or small plane.
Sometimes near the town pier, you can watch maybe 500 blue footed boobies doing their kamikaze dive bomb feeding. Take a trip down to
Los Tuneles which is such an amazing, amazing place. It's a labyrinth of lava arches inside the breakers with crystal clear water full of huge sea turtles, eagle rays, sea lions, fish, white tipped reef sharks and more. Turtles have developed something of a highway through there. You can stand on an arch (with 2 active volcanoes in the background) and watch them pass each other on the way from the mangroves to the open sea as if on an interstate with lanes clearly designated. Land before time visits and posing with penguins for photos if you wish. Los Tuneles is also a blue footed booby nesting ground. We always spot mantas just before entering and almost always get to snorkel with them. Last Nov, we had 9 males chasing 1 female. We left them after 30 minutes, but not before I got clipped. Though I am a strong advocate against touching any marine life, they were almost always close enough to touch.
You can also trek
Sierra Negra Volcano and if you do, I would highly recommend taking the extra jaunt over to Volcan Chico, a parasitic cone as opposed to separate volcano, where the vistas are magnificent to the sea and the landscape is usually best described as a lunarscape. Stunning site where you can see steam escaping from fumeroles and feel the heat of the lava beneath you...truly other wordly. Sierra Negra has the second largest caldera of an active volcano on the planet.
There's a fantastic campground half way up the slopes of Sierra Negra that is perfect for lunch after a trek. They have to be notified in advance, but everything they serve is from organic fruit and vegetable gardens on the stunning premises. They bake chicken and bread in outdoor lava rock ovens over fire. They are also a half way house for young tortoises after the Isabela breeding center and before being released back into the wild. Between Sierra Negra and Campo Duro, makes for a wonderful day in the highlands.
There's great snorkeling on your own from Isabela, including turtle cleaning stations where I've seen them on their hind legs like a dog begging to give the cleaner fish better access. The Breeding Center for tortoises is fascinating as Isabela has more species of tortoises than other islands due to AA lava fields they could not cross as well as the only flat back tortoises in the islands...some of which now live at the Breeding Center after being rescued from Cerro Azul's last eruption and bear the scars on their shells.
In addition to everything else, there's a 3 kilometer long white powdery sand beach, most of which is inside the National Park, therefore mostly empty and pristine. Marine iguanas nest through there. At places, you can snorkel and watch them feeding underwater. And always, turtles and sea lions.
Sorry to go on, but I absolutely love Isabela. I've gone with clients directly from a live-aboard to Isabela. I remember one marine biologist said he expected to be disappointed in Los Tuneles as I raved a little too much, but was surprised that instead, he was "in awe". Another LAB client of mine (Brit living in Belgium) said he didn't know which he liked best...diving Darwin and Wolf or our extension to Isabela. He finally concluded, "Let's put it this way...it would have been a travesty to have missed this."
Hotels over there begin too cheap to recommend and go up to about $400 per night. There are a couple in the $50-$60 pp per night range that are excellent and on the beach. Tours to Los Tuneles or Sierra Negra range from $60-$150 pp. You can get in more diving while there if you wish.
So unless you are an avid bird watcher, a LAB with an Isabela extension is as good as it gets if you are not doing back to back cruises, one live-aboard and one Naturalist cruise.
