So you don't want to setup a web farm just more of a mirrored scenario?
You can do this but it will be all dependent on how you set up your file sync and your database replication. You can do this but you'd need to setup a second web server and have server A sync files with server B. You can accomplish this with Microsoft's DFS.
Then for the database, you'd have in a real world scenario, 2 different SQL database servers where SQL db server 1 replicates to SQL db server 2. Then when web server 1 or db server 1 crashes, you do as you say and point your IP to the server 2.