diff --git a/setuptools/msvc.py b/setuptools/msvc.py
index 9c9a63568e..3ac0c97560 100644
--- a/setuptools/msvc.py
+++ b/setuptools/msvc.py
@@ -17,6 +17,8 @@
 
 from more_itertools import unique_everseen
 
+from ._path import StrPath
+
 import distutils.errors
 
 if TYPE_CHECKING:
@@ -135,7 +137,7 @@ def target_dir(self, hidex86=False, x64=False) -> str:
             else rf'\{self.target_cpu}'
         )
 
-    def cross_dir(self, forcex86=False):
+    def cross_dir(self, forcex86=False) -> str:
         r"""
         Cross platform specific subfolder.
 
@@ -306,7 +308,7 @@ def microsoft(self, key, x86=False):
         node64 = '' if self.pi.current_is_x86() or x86 else 'Wow6432Node'
         return os.path.join('Software', node64, 'Microsoft', key)
 
-    def lookup(self, key, name):
+    def lookup(self, key: str, name: str) -> str | None:
         """
         Look for values in registry in Microsoft software registry.
 
@@ -319,7 +321,7 @@ def lookup(self, key, name):
 
         Return
         ------
-        str
+        str | None
             value
         """
         key_read = winreg.KEY_READ
@@ -486,7 +488,7 @@ def _as_float_version(version):
         return float('.'.join(version.split('.')[:2]))
 
     @property
-    def VSInstallDir(self):
+    def VSInstallDir(self) -> str:
         """
         Microsoft Visual Studio directory.
 
@@ -504,7 +506,7 @@ def VSInstallDir(self):
         return self.ri.lookup(self.ri.vs, f'{self.vs_ver:0.1f}') or default
 
     @property
-    def VCInstallDir(self):
+    def VCInstallDir(self) -> str:
         """
         Microsoft Visual C++ directory.
 
@@ -608,7 +610,7 @@ def WindowsSdkLastVersion(self):
         return self._use_last_dir_name(os.path.join(self.WindowsSdkDir, 'lib'))
 
     @property
-    def WindowsSdkDir(self) -> str | None:  # noqa: C901  # is too complex (12)  # FIXME
+    def WindowsSdkDir(self) -> str:  # noqa: C901  # is too complex (12)  # FIXME
         """
         Microsoft Windows SDK directory.
 
@@ -651,13 +653,13 @@ def WindowsSdkDir(self) -> str | None:  # noqa: C901  # is too complex (12)  # F
         return sdkdir
 
     @property
-    def WindowsSDKExecutablePath(self):
+    def WindowsSDKExecutablePath(self) -> str | None:
         """
         Microsoft Windows SDK executable directory.
 
         Return
         ------
-        str
+        str | None
             path
         """
         # Find WinSDK NetFx Tools registry dir name
@@ -688,7 +690,7 @@ def WindowsSDKExecutablePath(self):
         return None
 
     @property
-    def FSharpInstallDir(self):
+    def FSharpInstallDir(self) -> str:
         """
         Microsoft Visual F# directory.
 
@@ -701,7 +703,7 @@ def FSharpInstallDir(self):
         return self.ri.lookup(path, 'productdir') or ''
 
     @property
-    def UniversalCRTSdkDir(self):
+    def UniversalCRTSdkDir(self) -> str:
         """
         Microsoft Universal CRT SDK directory.
 
@@ -717,9 +719,9 @@ def UniversalCRTSdkDir(self):
         for ver in vers:
             sdkdir = self.ri.lookup(self.ri.windows_kits_roots, f'kitsroot{ver}')
             if sdkdir:
-                return sdkdir or ''
+                return sdkdir
 
-        return None
+        return ''
 
     @property
     def UniversalCRTSdkLastVersion(self):
@@ -751,16 +753,15 @@ def NetFxSdkVersion(self):
         )
 
     @property
-    def NetFxSdkDir(self):
+    def NetFxSdkDir(self) -> str | None:
         """
         Microsoft .NET Framework SDK directory.
 
         Return
         ------
-        str
+        str | None
             path
         """
-        sdkdir = ''
         for ver in self.NetFxSdkVersion:
             loc = os.path.join(self.ri.netfx_sdk, ver)
             sdkdir = self.ri.lookup(loc, 'kitsinstallationfolder')
@@ -769,7 +770,7 @@ def NetFxSdkDir(self):
         return sdkdir
 
     @property
-    def FrameworkDir32(self):
+    def FrameworkDir32(self) -> str:
         """
         Microsoft .NET Framework 32bit directory.
 
@@ -785,7 +786,7 @@ def FrameworkDir32(self):
         return self.ri.lookup(self.ri.vc, 'frameworkdir32') or guess_fw
 
     @property
-    def FrameworkDir64(self):
+    def FrameworkDir64(self) -> str:
         """
         Microsoft .NET Framework 64bit directory.
 
@@ -855,7 +856,7 @@ def _find_dot_net_versions(self, bits) -> tuple[str, ...]:
         return ()
 
     @staticmethod
-    def _use_last_dir_name(path, prefix=''):
+    def _use_last_dir_name(path: StrPath, prefix: str = '') -> str:
         """
         Return name of the last dir in path or '' if no dir found.
 
@@ -877,7 +878,7 @@ def _use_last_dir_name(path, prefix=''):
             if os.path.isdir(os.path.join(path, dir_name))
             and dir_name.startswith(prefix)
         )
-        return next(matching_dirs, None) or ''
+        return next(matching_dirs, '')
 
 
 class _EnvironmentDict(TypedDict):
@@ -1191,7 +1192,7 @@ def _sdk_tools(self):
             yield self.si.WindowsSDKExecutablePath
 
     @property
-    def _sdk_subdir(self):
+    def _sdk_subdir(self) -> str:
         """
         Microsoft Windows SDK version subdir.
 
@@ -1370,7 +1371,7 @@ def UCRTIncludes(self):
         return [os.path.join(include, f'{self._ucrt_subdir}ucrt')]
 
     @property
-    def _ucrt_subdir(self):
+    def _ucrt_subdir(self) -> str:
         """
         Microsoft Universal C Runtime SDK version subdir.