You may sign the log at any time but you may not post a "found it" log until you have fulfilled the requirements for this cache. All cache types may be used to fulfill the requirements for this challenge.
No need to post qualifications as long as your Stats page on geocaching.com is available for public viewing. Any found it logs by anyone who has not met qualification will be deleted.
These caches are located along country roads. Please exercise caution going into ditches especially during winter months. Watch where you step.