diff --git a/src/abovepy/_mosaic.py b/src/abovepy/_mosaic.py
index 2a451ed..e0c9bd2 100644
--- a/src/abovepy/_mosaic.py
+++ b/src/abovepy/_mosaic.py
@@ -103,7 +103,17 @@ def _build_vrt(
     Path
         Path to the created VRT file.
     """
-    from osgeo import gdal
+    try:
+        from osgeo import gdal
+    except ImportError as exc:
+        from abovepy._exceptions import MosaicError
+
+        raise MosaicError(
+            "VRT construction requires the GDAL Python bindings, which are not "
+            "installed by default. Install with `conda install -c conda-forge gdal` "
+            "(recommended) or `pip install gdal` (requires matching system GDAL headers). "
+            "Alternatively, pass an output path ending in `.tif` to merge via rasterio."
+        ) from exc
 
     gdal.UseExceptions()
 
diff --git a/tests/test_integration.py b/tests/test_integration.py
index b75271f..9bb4e4e 100644
--- a/tests/test_integration.py
+++ b/tests/test_integration.py
@@ -36,8 +36,8 @@ def test_search_dem_phase3_frankfort(self, frankfort_bbox):
         """Search returns DEM tiles for the Frankfort area."""
         tiles = abovepy.search(bbox=frankfort_bbox, product="dem_phase3", max_items=10)
         assert len(tiles) > 0
-        assert "tile_id" in tiles.columns
-        assert "asset_url" in tiles.columns
+        assert "tile_id" in tiles.tiles.columns
+        assert "asset_url" in tiles.tiles.columns
 
     def test_search_by_county(self):
         """County-based search returns results."""
@@ -59,7 +59,7 @@ def test_asset_urls_are_accessible(self, frankfort_bbox):
         import httpx
 
         tiles = abovepy.search(bbox=frankfort_bbox, product="dem_phase3", max_items=1)
-        url = tiles.iloc[0]["asset_url"]
+        url = tiles.tiles.iloc[0]["asset_url"]
         resp = httpx.head(url, follow_redirects=True, timeout=30)
         assert resp.status_code == 200
 
@@ -90,7 +90,7 @@ def test_dem_products(self, frankfort_bbox, product):
         """DEM products return tiles for Frankfort area."""
         tiles = abovepy.search(bbox=frankfort_bbox, product=product, max_items=3)
         assert len(tiles) > 0
-        assert tiles.iloc[0]["product"] == product
+        assert tiles.tiles.iloc[0]["product"] == product
 
     @pytest.mark.parametrize(
         "product",
@@ -113,9 +113,11 @@ def test_ortho_products(self, frankfort_bbox, product):
             "laz_phase3",
         ],
     )
-    def test_laz_products(self, frankfort_bbox, product):
-        """LiDAR products return tiles for Frankfort area."""
-        tiles = abovepy.search(bbox=frankfort_bbox, product=product, max_items=3)
+    def test_laz_products(self, pike_county_bbox, product):
+        """LiDAR products return tiles. Uses Pike County because Phase 1 LAZ
+        does not cover Franklin County (Frankfort); Phase 1 was flown
+        county-by-county 2010-2017 and Franklin was not in that batch."""
+        tiles = abovepy.search(bbox=pike_county_bbox, product=product, max_items=3)
         assert len(tiles) > 0
 
 
@@ -198,7 +200,7 @@ class TestLiveRead:
     def test_read_cog_windowed(self, frankfort_bbox):
         """Read a real tile with a windowed bbox."""
         tiles = abovepy.search(bbox=frankfort_bbox, product="dem_phase3", max_items=1)
-        url = tiles.iloc[0]["asset_url"]
+        url = tiles.tiles.iloc[0]["asset_url"]
         data, profile = abovepy.read(url, bbox=frankfort_bbox)
         assert data.shape[0] >= 1
         assert profile["crs"] is not None
@@ -207,7 +209,7 @@ def test_read_cog_windowed(self, frankfort_bbox):
     def test_read_full_tile(self, frankfort_bbox):
         """Read a full tile without bbox clipping."""
         tiles = abovepy.search(bbox=frankfort_bbox, product="dem_phase3", max_items=1)
-        url = tiles.iloc[0]["asset_url"]
+        url = tiles.tiles.iloc[0]["asset_url"]
         data, profile = abovepy.read(url)
         assert data.shape[1] > 0
         assert data.shape[2] > 0
@@ -216,7 +218,7 @@ def test_read_full_tile(self, frankfort_bbox):
     def test_read_returns_epsg3089(self, frankfort_bbox):
         """Read tile CRS should be EPSG:3089."""
         tiles = abovepy.search(bbox=frankfort_bbox, product="dem_phase3", max_items=1)
-        url = tiles.iloc[0]["asset_url"]
+        url = tiles.tiles.iloc[0]["asset_url"]
         _, profile = abovepy.read(url)
         crs_str = str(profile["crs"])
         assert "3089" in crs_str
@@ -253,6 +255,10 @@ def test_download_skip_existing(self, frankfort_bbox):
     @pytest.mark.slow
     def test_mosaic_vrt(self, frankfort_bbox):
         """Download 2 tiles, mosaic to VRT, verify it's readable."""
+        pytest.importorskip(
+            "osgeo",
+            reason="VRT construction requires GDAL Python bindings (not a default runtime dep).",
+        )
         tiles = abovepy.search(bbox=frankfort_bbox, product="dem_phase3", max_items=2)
         if len(tiles) < 2:
             pytest.skip("Need at least 2 tiles for mosaic test")
@@ -308,6 +314,6 @@ def test_laz_tile_url_accessible(self, frankfort_bbox):
         tiles = abovepy.search(bbox=frankfort_bbox, product="laz_phase2", max_items=1)
         if tiles.empty:
             pytest.skip("No COPC tiles found in Frankfort area")
-        url = tiles.iloc[0]["asset_url"]
+        url = tiles.tiles.iloc[0]["asset_url"]
         resp = httpx.head(url, follow_redirects=True, timeout=30)
         assert resp.status_code == 200