Turn Off Transaction Log During Schema Change?

Is it possible to turn off transaction logging when making a table schema change? For example, when expanding a varchar field from 10 to 40 characters? This is occurring on a hosted site for a table with about 150,000 records. The db size is 200 Mb. If I try this normally with transaction logging enabled, I get the dreaded log file is full message, even if I first truncate it.

I was thinking about doing the following instead:

taking the db offline
creating a backup
disabling logging
change the schema
re-enable logging
put db back online

If a problem occurs during the schema change, I would just restore from the backup. Please let me know the following:

Is it possible to turn of the transaction logging for the schema change?
Do you see any problems with the above.
Alternatives?

One alternative is to look into increasing the db size. A second is to add a new field (named temp) to the table, copy the old field to the new field, delete the old field, add another field (with the original field name) with the new schema, copy the temp field to the new field, and finally delete the temp field. This should require less space in the transaction log. Unfortnately, it could possibly affect some linked Access databases with the new field order.

Thanks in advance.