The standard way to Upgrade Android version is to ensure you have essentials backed up, Edit, return the device to Stock Rom [1], follow the install instructions (just as a fresh install), including Format data, then restore the backup.
One can see the published builds for dream2lte stable here. There is no need to incrementally upgrade. Take either latest v2.0-r or one down v1.21-r.
[1] Device dependent, It is wise to check Settings > About phone > Tap Android version and check your Vendor Security Patch Level and Baseband version. You can check with a Firmware source like one of these
to ensure you are on the latest firmware. If you are on latest firmware release (SW-rev) you may omit return to Stock ROM before you upgrade.
However I would wait 24 - 48 hours in case the OTA Upgrade arrives, or in case devs decide to put the service online on account of several stable users having missed it earlier.