For InstallScript projects, there aren't really any changes necessary unless you would like to install files to the 64-bit System32 folder or registry data to the 64-bit portion of HKLM\Software.
To install files to the 64-bit System32 folder, override the Installing and Installed events for features that only contain components installing to this path. In the Installing events, disable WOW64FSREDIRECTION, and in the Installed events, enable WOW64FSREDIRECTION. (Repeat this also for the Uninstalling and Uninstalled events to ensure these files are removed correctly during uninstall.)
To install registry data to the 64-bit portion of HKLM\Software, use the InstallScript registry functions to create the registry data with REGDB_OPTION_WOW64_64KEY set in REGDB_OPTIONS before calling the registry functions.
To install resources to any other locations does not require any additional work than installing any typical resource on a 32-bit machine.
